MCH does have a rotation:
Split Shot > Get Split Proc > Slug Shot > Get Slug Proc > Split Shot > Clean Shot
I > II > I > III
Then make sure to have Hot Shot and Lead Shot up and weave your oGCDs in with them.
IF you can, you'll want those oGCDs to line up with Wildfire.

As for BRD, you'll just want to keep your DoTs and Straight Shot up, while weaving your oGCD with Heavy Shot.