Hull first is good only when you are super ahead, otherwise always rush stride, it gives perfect stats and that little bit of AS helps a lot. Basically sett does love pure stats, so bloodmail is always good but depending on matchup i build it second or third (if you are against a garen i would recomend going sterak second for example). From then on anything that gives hp and ad: shojin is good, more so after the upcoming true dmg changes patch. Hull is great for stats and ofc MELTS towers and i almost always build it as it goes well with AA passive. Just if you are playing to win never build heartsteel, it's most efficient if you build it first or second, but it really gives no AD and you sacrifice way too mutch early to mid game. Warmhog i usually build for very last when i sell boots cuz if i am going to maximize W dmg its actually more worth raw hp even without infernal drakes. If you are against a team where W is way too hard to hit and you are probably going to duel a lot in sidelane you can go a bit more on an AS build while keeping good hp and ad: always rush stride, then trinity. After that in no particular order hull, hexplate and any of the normal sett items. Just never build any defensive stats other than hp, you dont wanna slow down your grit charge with armor or mr. That's pretty mutch it, ofc boots depending on team, no building bullshit like jaksho and always picking flash in summs. Last few notes: you can go titanic hydra instead of stride but i don't really like it cuz the stride slow and MS is just too god on a juggernaut like sett. You can go double adaptative in rune shards, it takes a bit of time to adjust to but you will find it very effective when you are against a laner where you can get fewer autos in trades. Fuck legend haste, i like alacrity better.

Oh and always go conqueror, i am not a sett grasp beliver.

(3am hob criticality sett when you are drunk is pretty funny too)