%w.att,? Total Damage % ? huh?

Would need confirmation from dual bladers. Boss damage on one dagger or katara should give both the boss damage bonus, meaning you only need one piece to have it.

Doesn't stack with Dagger/Blade. Tested before.

ATTACKS is modified before ammo/star and attack buff, so basically just your "base attack" that you can gather from your equip/blessing/skill. Meaning it should be (base attack x ATTACKS % + (ammo/star/attack pot/buff), then modified by echo after.

Okay.

Total damage %s stacks, so ideally you would want 30%, total damage, total damage, total damage, ATTACKS, ATTACKS, spread across dagger and katara, order doesn't matter but of course having total damage on first line is a bonus.

Total Damage% doesn't stack.

Reason why you don't want % luk is the increase in less compared to total damage and ATTACKS once your % luk gets higher. Since you don't boss a lot, I think having 3 total damages, and 3 ATTACKS across is better. If you use apples or high attack pots a lot (or your weapon att is considerably low, say 150 ish), 4 total damages and 2 ATTACKS might be better.

Not true. Dual Bladers kill fast anyway so having 30% boss damage would be more beneficial even if you don't even boss. At 153, I 1-hit skeles almost all the time, with mediocre gear. So having %LUK and Boss Damage% would be better.