PA Olivia weapon refinement

Hi everyone,

I was able to summon a Grey Olivia On my first summon circle so I'm verry happy. Her IVs are +Def -spd, far from optimal ... I'm going to use her as a healer with WoM and breath of life.

My question is : do you think it is still worthy to give her the speed refinment ? With 31 and only +2 spd she won't even reach the speed of a neutral Olivia. So I thought I would raise one of her defensive stat instead : Should I go all out on her def since she already has the boon or focus on her res since it's already higher ? With double distant defense seal she might be able to survive something that way, or am I wrong ?
Thanks for any feedback :)