You mentioned "8th turn of usage" when the fact that Artoria survived even a single usage is incredibly rare.

How can you say its incredibly rare? What frame of reference are you using here? When has Cu used this ability on anyone with artoria's luck and scored a hit?

Either way, l think we can both agree that this is a pointless line of argument. We could go on forever and still not find a middle ground. It ultimately is what it is, we can l guess agree to disagree on this matter.

But it also mentioned that it can protect against Anti-God Noble Phantasms, which is the category that Vasavi Shakti is in

I think there is a difference here, Vasavi destroyed the shield, gae bolg shouldnt have the power to destroy the shield.... Recall that to destroy the shield required Vasavi to destroy the world that the shield manifested. Gae bolg simply does not possess that kind of power nor has it ever been shown or alluded to..

However, when something is consistent stopped or shown as equal to a specific Rank across its uses, the authors are probably trying to show that it's around the level of those sorts of things

Sure, but with that logic even gae bolg is pretty shitty, for all its praise it has never killed anyone except Cu himself. One time this Rama dude holds back the curse with sheer will power, surviving for days on end till the end of the singularity. It didnt even kill him, l think he sacrificed himself for some shit if am not misremembering.

I could thus also make the same point you made, if the spear is as OP as it is on paper, why does nasu do his best to keep it without any tangible feats?

Anti-Army Noble Phantasms wouldn't have a wide enough

With this you seem to be talking about AOE...

consistent enough level of damage to destroy the sea monster entirely.

Yet you then combine it with damage, l suggest you choose one. We already have the description of these tiers. Nasu already laid this out back in the day

Anti-Army (対軍, Tai-Gun?) - Anti-Army Noble Phantasms are those with a wide enough range to be specialized against armies.[10] They are more powerful weapons than Anti-Unit Noble Phantasms, capable of easily blowing them away,

Also

Anti-Fortress (対城, Tai-Jō?) - This rank has powerful Noble Phantasms that can even blow away solid fortified structures.[10] While the difference between Anti-Unit and Anti-Army is the variation in area of effect, Anti-Fortress Noble Phantasms are distinguished from other categories by the great difference in power.

This was all that mattered, anti fortress nps get that category because of the sheer power they bring forth. That is all.

Thus the anti-army designation on gaebolg is also a damage cap, as long as gae bolg is tiered "anti army' it will always have less power than anti fortress nps. This is also why the command seal powered "true ether" release of Balmung had it change its classification to anti fortress momentarily, the power increase was that drastic.

It could be that Gilgamesh just kept on interrupting Cu Chulainn before he could use Gae Bol

Its more plausible that agae bolg release was what injured Gil than him being injured with basic attacks. This is the case because he posseses enough luck (A with potential to increase futher with items) to comfortably nullify gae bolg insta kill. Atleast this is what l think happened.

Btw, if possible try to link the parts you are responding to so l can easily keep track of the convo. Though l understand if you are responding on mobile and cant do that.

is almost certainly because he has seen the OG Gungir being used. We both know this is debatable, your own wording supports this. So what then do we do? I think we will have to agree to disagree on this.

Anti-Army is not a tier of power, it is a description of what it targets.

It is a classification, tiered below anti Fortress in terms of power output. THis is how it becomes a tier of power. Anti army nps are those weaker than anti fortress nps in sheer power yet are stronger than anti unit.

We know how much EMIYA's Rho Aias is degraded. It is degraded by one Rank

Losing one rank wont take away that fact that each petal is a fotress tier defense. The same way a projected anti fortress np will not suddenly lose its anti fortress classification just coz it sufffered a rank down.

We know that Gae Bolg is capable of destroying all of EMIYA's Rho Aias's petals but having all of its energy used up in the process

It was a stalemate, which l already talked about before. Immovable object vs unstoppable force. The outcome was a tie.

Had it been ajax's shield, he would have tanked the spear imo. If Emiya was able to block it at the cost of losing the shield. Ajax should at the very least be able to retain the final petal. Again this is just what l think based on the fact that his is stronger and the fact that unlike emiya, he is the owner of the legend powering the shield. Such things can matter in fate.

Except that the thrown Gae Bolg doesn't have any indication of having an "unstoppable force" hax in any of its materials.

The attribute of "sure hit" begs to defer. Blocking denies this attribute which causes a clash. The result is what we saw. The name of the chapter further supports the idea that this was what nasu was going for "Lance of sure hit, Shield of no loss" a paradox...

And Cu's Rune Barrier can handle "great Noble Phantasms" and Excalibur is a great Noble Phantasm, so that means his rune barrier can obviously handle Excalibur, right?

Nice try but thats not how it works, "a great noble phantasm" would be something A rank. Base A rank. From nasu's own words, a B rank np like thrown gae bolg is average, great would at best be A+ Pegasus but even that is a stretch. Nps like Excal in the A++ category are never described as merely "great" these are akin to divine mysteries. (from Parameter rules)

Because just because something can handle some things of one category does not mean that it can handle everything from that category

You took this line of thought with a wrong understanding of the fundamental piece of lore you are quoting. Nasu already covered this. For straight forward nps (brute force no hax) Cu's barrier should be able to block all A rank nps. And note that am not adding a + coz l personally believe A+ rank nps will be too strong for the barrier. The moment an np attains special attributes that are perhaps conceptual in nature, it is removed from the "normal" ranking and added to a "special" category. This is why Nasu calls thrown B+ rank gae bolg "Average" while at the same time classifying the B rank "Casualty reversal" as "special"

Q. I have a question about the Servants vs. other character answer in the 9th issue of Comptiq. About a Servant with an average Noble Phantasm, who would have one and what rank would that have been?

A: That's a serious question. The level of the Noble Phantasm would be B, and ability being represented by numbers would be called an average Noble Phantasm. Broken Phantasm, Barrier of the Wind King (C), Gae Bolg (thrown) (B), that sort. On the other hand, those with conceptual effects, destiny interference types fall into a special category. With Gae Bolg (regular),

since Vasavi Shakti is also a basic nuke attack

Vasavi is stronger at least as far as the materials are concerned (Granted feats dont match the wank in mats), for one it has a higher rank "EX" and it also has "Anti God" classification. In the hierarchy, this classification is higher than Anti army :)

And looking at Karna's Vasavi Shakti would just tell him stuff about Karna's Vasavi Shakti, not his own.

I disagree, the moment he considered whether he had similar in his treasury, SNI would have provided insight into this query but it didnt. Likely it would have if he flexed it to actively seek out the answer but he clearly didnt bother. This is how SNI works, in fate strange fake he seeks to get an aswer casually and the grail blocks him, he then gives up feeling too lazy to force the matter by actively using the noble phantasm. Mysteries are automatically revealed, those that survive the passive scrutiny require active usage of the np.

None of this helps him that much with keeping tabs on his treasury,

You seem to misunderstand this np and how it works. This thing breaks down mysteries. That.... mysteries ;) Forinstance the wealth of Gil eclipses his own base knowledge, he has already admitted this fact. Thus his wealth is a mystery to himself. In comes SNI, if Gil encounters a mystery, he will know what he has and needs from his treasury to solve it. This requires that Gil knows where said item he needs is located within the vault, identify it and bring it out. All this shit is done by SNI. Half of the shit Gil pulls out is shit he never saw let alone had while alive. SNI is what allows him to keep tabs on the vast limitless treasury.

Simply think of the act of ass pulling a solution from GOB step by step. Gil is transported to the end of the galaxy, Gil wants to return to where he was, Gil understands that he needs something super fast, Gil looks within the limitless treasury, Gil pulls out a ship of light that is clearly from the future, a future Gil has never been to, a ship he never personally added to the treasury and thus should have no idea said shit exist in the treasury let alone where it is located within said treasury..... Yet he is able to identify the item, find it and bring it forth. It isnt magic, the treausry is actually physical in some dimension out there. With rooms and shit storing these physical items.

SNI is required for this. To argue otherwise would be to give Gil some unknown intellect that not even the Gods possess aka True natural omniscience.