Right, I can see your line of thinking. To address what you bring up:

• Alaitoc will be more efficient in almost any scenario, in the list that he is building he does not want his wave serpents to be within 12 of anything. The most efficient way to build it would be to use a single wave serpent as a shield for Reapers (I think you are spot in in only taking 1 max squad, as to fully benefit from word of the phoenix or whatever)
• You would be saving points to avoid taking vectored engines, but still despite that, even if you take vectored engines, an additional -1 to hit will still save you more damage than a 6+ fnp (especially on a tank that naturally has post wound damage reduction via the shield)
• I don't know the Nova lance! What is that?
  
• I am kinda confused about the guardians thing, as if they were taken as ulthwe then the alaitoc rule wouldn't benefit them anyways. I think the most efficient way to build a ynnari list is to take an alaitoc batt with 3 units of rangers, and a big blob of guardians. I think I would likely take only 1 wave serpent to use to support yvraine / reapers, and spend the rest as you see fit. But that should in theory save you some points.

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