You will not have perfect balance up for every pull. For an average pull You will be able to use rockbreaker every 3rd gcd (184.6 lets call it 185 to put the numbers in your favor, fully buffed). While NIN will be able to use death blossom every GCD (120 potency) and DRG being able to use doom spike every GCD as well (160 potency). Now even if we were to get into burst as you were talking about howling fist. Death blossom + double katon for NIN, and for DRG we have doom spike + dragon fire dive. The only time you would even remotely pull ahead is when you have PB up and when that falls off, you go back down again.
