More input on a few things:

1. I use Thunder III as my initial attack if I can shave some time off it before the tank pulls. Helps if you can hear your tank and he tells you right when he'll attack so you can maximize your DPS. Other than that it's Thunder II, or if I have Swiftcast.

2. For Swiftcast, I usually use it right away after the initial Thunder III, on Fire III. This never pulls aggro unless you severely outgear the tank; it puts you immediately into AH3 and lets you use your non-GCDs during the recast to buff your Fire -> Firestarter phase (your highest DPS phase). After that, since UI3 > Fire III is so quick, I'll use it on Thunder III or on Flare as a finisher.

3. For Convert, I use it during boss fights when I'm in the Fire -> Firestarter phase, preferably while I have Raging Strikes or an INT potion up. Also of course it's amazing for double Flare.