Movement with Onslaught. Upheaval more or less on CD, as long as it's also going to be available for Zerk+IR. Otherwise I just use Onslaught to manage gauge so I don't go over the cap.

As for Zerk+IR combo, you can fit two Onslaughts and an Upheaval in the combo along with your 6 FC's.

80 gauge > Storm's Eye combo (100) > Zerk > Heavy Swing+IR+Onslaught > Maim+Upheaval > FC > FC+Inf > FC > Storm's Path > FCx3+Onslaught.

Zerk will end right before the final FC, so if you're anal about that stuff you can delay the Zerk use until it's after the Heavy Swing and combo it with IR and Upheaval. It's a big cumbersome because that's 3 oGCD's at once, but the IR animation tends to be overwritten very easily so there's not a lot of clipping, at least for me at a 2.4 GCD.