The priority list ended up as being something like

HP IDC TTT
HP TTT TTT
H IDC P TTT
H TTT TTT
HP IDC TTT
HP TTT TTT
HP

It seems with a 2.5 GCD you will split H and P somewhere. Likely this is due to a clipping being impossible because of buffs.

If you want, I can feed in a hard rotation too, and compare to see which does more damage.