How is GSpy doin more damage than vader by a significant margin?
Vader has 30% more damage on culling's basic damage, 30% bonus from his lead and the culling damage bonus per debuff is 20% more. Thats at least a double damage bonus already.
GSpy gets bonuses per buff on the boss and also any buffs on himself but these are additive where they add % of the ability base damage modified by any buffs. At best u have offense up on the boss, stealth and crit up on gspy which is the equivalent of 3 dots damage wise. Dots needs to be in the 30s to get that kind of damage from vader.
How are you getting this descrepancy?