I've googled it but I cant fine a 100% yes or no.

I ask because my gun is 12% total, 9% total and 30% boss...
If it doesnt work I might just cube till 50+% boss

Yes they do stack.

But if you mainly boss and you dont mind spending the NX, 50% boss is better than total damage by far.

I got 30% total on my dagger and I hit numbers way beyond my range can. I'm sure it stacks. Having your range increase by an invisible 30% is pretty useful for training.

Database wrote:

Yes they do stack.

But if you mainly boss and you dont mind spending the NX, 50% boss is better than total damage by far.

51% on boss with total dmg or 50% boss , wat