Eirika for Refinery Weapon

For me, it’s about preference. I had a +atk and +spd eirika that was built already but in the end I chose +spd as her boon since I prefer defensive boons on support units. Although, if given the chance, she can also be a threatening unit.

I would go +atk, she has good speed and desperately needs atk, and it's also a superboon.