So, we have a guardian that is starting on Bestia and we are pre. casting flyby and at least I start with using everything I have since I want to break your damn first place parse. I do admit that I or one of my gunslinger friends steals aggro but that is always before our tank has done his second taunt so I never take more then one hit until the tank has gotten the boss back. We use three tanks so during our first tries we all had guard on our three best DPS and then none of us ever got aggro and the tank held it safely at start.
So, to answer your question, no we don't hold back the slightest :P
Even with bestia knocking the tanks down ? They claim that is the reason why they can' build optimal and top threat. last night in 8man i waited 15 whole seconds before starting because got tired of getting aggro and being "called at."
i wonder what your tanks are doing :-|
they're guardian and vanguard tanks btw