I've been experimenting a bit with my Hunter and i do most DPS as Marksman compared to the other 2 specs.
My rotation so far is: Serpent Sting, Chimera shot, Arcane shot(But only if you have enough focus to use Chimera shot when its of CD) and Steady Shot.
I'm not sure wheter to use Kill Command or not. Will check in the next raid. And i will also know exactly what talent points to use. its pretty straight forward atm but you have like 4-5 points you can swap around and im not 100% sure what is giving the most dps.
Update inc soon