I managed to solve my crit rate problem with 2p Woodpecker. Ideally I should have had better Crit substats so I could get ATK% 2p instead of woodpecker, but oh well.

I need some engine advice.
If I equip Hellfire Gears, I will have 3473 ATK.
If I equip Fossil Core, I will have 3281 ATK.
Options:
1. should I go for Hellfire Gears and max Jufufu's buffs?
2. should I go for Fossil Core and give Jufufu more Stuns?
3. should I reroll my crappy discs so I can obtain Fossil Core with max buffs?