Most optimal Summer Camilla IVs?

I would assume +Spd/-Res considering her base tome is a Desperation weapon.

I think the ideal is +Spd - Res. Especially if running blade tome, you want that extra speed. Not to mention the increase in the no. of units with high speed as of late.

+spd IV will generally be better for either variety of Camilla (desperation tome or bladetome) to ensure more follow-up attacks. With 16 res from the bane, she will still be able to take 55 neutral magic dmg (single hit), which is not horrible and the neutral defense will allow her to take a hit from a DC unit and survive, which is much more valuable for a blade/offensive mage.

Depends what you're going for I think, either works, but I'd personally pick +Spd bc either you use her weapon for desperation, in which case more speed is nice, or you give her a blade tome and buffs, in which case her atk gets knocked through the roof anyways.