Just to add to this, as it is my ideal set up as well, if you are world buffed (kings + zg) you can replace pussiant with draconic might and flameguards with t1 and receive equal hit, equal crit, and gain 12ap.
It's not 8%. I was running 8% with 309 skill last two weeks. I noticed I had a missed bloodthirst on firemaw and ragnaros. I couldn't figure out why so I paid more attention to my logs and learned i was missing <1% of my specials. I have to say after reading this thread and using 9% hit for the last week, the 9% hit formula is correct. With 9% hit I haven't missed a single special since.
Edit: Just want to update as to not misinform anyone. 8% @ 300 skill you will miss specials. Im 309 in swords but my main hand was a fist weapon. Hense why it was missing bloodthirst @ 8% and hasnt been @ 9%. I imagine if I was a sword in the mainhand 8%@309 would be fine but I havnt been able to test.