Help with game Mechanic , Skill: Spiral Pierce

Hello, Theres something im quite unsure about the forumula. Can someone help me out please? So what is the most important factor in this skill? Weight , card or refine rate?

the most important is weight, atk just add slight more dmg :S, which means for spiral build, u dont really need str, get vit and good dex, for faster cast, and lets say ur base dmg is 10k, if u put 20% size, it means 10k+(10k*20%)

imo, ur build should be based on what is your enemy is.
if u want to manage one hit, maybe u'll need some atk, your choice.

Thanks Ciel . + 1 bish point .