Another advice for you GlacialRet and everyone who has some DPS problems.
I found this video in WotLK and have been confirmed with my playstyle.
Guide to Top DPS By Kripparrian - World of Warcraft Movies
These facts still apply to the game and will never change and have never changed.
Also I would recommend to NOT use PTT for Vent,TS3,Mumble,etc.
Every PTT push is a loss in efficiency, IMO. This applies to all Specs.
If you want to use PTT anyway. Just do not Keybind it to an ability modifier.
Get a new Button on your mouse or elsewhere.
A friend of mine uses a pedal to talk on TS3, crazy but effective.