Archer/Hunter Help Need Help With Powders

Hey everyone. So I have my build together now (except for hive bow) and I'm wondering if I should add powders to my gear and if so which?
heres my build so you can look at what i have. https://wynndata.tk/s/8nSjAf
its a Water Spell build with these stats for defense:
❤ Health: 9305
✹ Fire Defense: 276
❉ Water Defense: 578
❋ Air Defense: 203
✦ Thunder Defense: -116
✤ Earth Defense: 276

So my question is which powders to use for the passive ability/abilities and to maybe balance out my thunder weakness.
also another question about that ^^^. Can you have multiple passive abilities? say on helmet air ability (I mean ability from 2x Tier 4+ powders) and have Water on your Chestplate? giving you both their passive (air dodge pasive where more damage if close to a mob and water idk the bonus out of my head)

So basically which powders should i use on what armor and why that powder? (and which bonuses) or if i should keep most stuff blank and only add powders for a passive bonus

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Also yes i have quite some rainbows in my build but i needed to for the skillpoints D:

 

air only gives air% dmg and water only gives water% dmg so you can only use water

 

put 2 t6 waters 1 thunder on stardust
2 waters 1 thunder on aquarius
2 waters on sanc
2 waters 2 thunders on paradox

 

???