Alm answered my call (nuke vs quad)

It seems like quad Alm wouldn't be fighting every round of combat given he'll be taking a hit if he doesn't finish his foe in his first two strikes. Maybe for the C Slot the speed wave (or attack wave) that matches the turn he gets healed from Falchion (even?) would be good.

Also, a healing special could work since Mystic Boost would cover the recoil damage but not much more.

Go with +atk. Spd is too niche. He should be one shoting most enemies in PP.

+spd shouldn't be taken to quad. But more as a defensive measure to avoid some enemy phase doubles in a pinch

I have to agree with +Atk as even with a speed boon he only gets so much while he can nuke enough enemies with an attack boon. If you can debuff the enemies enough you'll actually two shot them often enough.