RE: Boss Damage stacking.

Does Sudden Raid work with Mirror Image? I don't remember, but I'm leaning towards no.

No.

Does Tornado Spin use your damage range? I recall testing it myself but I can't recall what the results were.

28188*250%*.75*1.6*1.08 = 91329
40269*250%*.75*1.6*1.08 = 130471

45797/126271 = 36.2%
126271*.7 = 88389
I don't think so.

Does the boss damage potential from a dagger affect katara damage and vice versa?

Not sure what you're asking but I have 30% boss on my dagger and on my blade.

Oh. Not sure. I wonder if this is the case.

Anyways. I believe you should be able to test with Mirror Image on an attack. Normally, Mirror Image will do 70% of the damage a skill inflicts. With the +8% total damage potential, this is increased to 75.6%. With 30% Boss Damage this should be increased to 98.28% if it stacks with +8% total damage. If not, it would be 91%. If 30% Boss Damage stacks (additively), with total damage it would be 120.96%. Without total damage, it would be 112%.

Otherwise, your math appears to be correct, but if the above works, you can double check easily. Otherwise, I'm horribly mistaken about Mirror Image and Boss Damage.

I'll try this out later.