If I were you, I would gem for as much intellect as I could, without losing whatever secondary stat I wanted, like... all of them.
I would probably use the +80 int +160 haste gems, or maybe +80 int +160 crit gems, as crit and haste are roughly worth the same (atleast on my ilvl of 508).
Try reforging to a haste point where you feel comfortable casting Incinerates while under Backdraft and raidbuffed!
That point, for me, is around 6000 haste. And with 6000 haste raidbuffed and under Backdraft I cast my Incinerates at a speed where I don't need to spam the hell out of my button, which I hate!
After you found a point, let's say 5000 haste, go and reforge crit to roughly the same, and then take the rest into mastery, as I saw you were using GoSup!
Atleast this is how I do it atm, and it works out super great!