Hm, that rotation seems a little random to me.
I use; prepot, immo, RoF (Only for trinket Proc(Cosmos)), conf x2, spamming 4 fast Ini, casting Dark Soul (Having all the trinkets and prepot still up) and can then use 3 CB fully int procced and with Dark Soul.
I can't say that I use RoF on a Singletarget boss, unless I want Cosmos to proc when I have Dark Soul of CD or other trinket procs and a line of Shadowburn/Chaos.. comming up. For me it's a little waste of time, since it's one GCD. But if someone can see some improvement of the DMG by having RoF up even on singletarget, please correct me.
For the reforge/gems. I personally go full out of Mastery with Supremacy and Observer. (Deppends on fight tho, else I choose the Imp with Demon hunting glyph.)