I finally figured out a way to get the last 5 targets consistently; C-Stick.

The way aerials work in SSF2 is that you have to both move the control stick to the direction you want and press attack. Unfortunately, this moves you far in the air and it can be difficult to realign yourself to where you need to go. However, with the C-stick you can do an aerial without having to move an inch. This means you can move around Jiggs without having to slow down or reroute. So I traded my Grab and Shield keys for B-air and U-air respectively. This is what changed everything for me, as I can now do the optimal route more easily and get more consistent times.

I fully believe I can push my time further, and the idea of holding the WR doesn't seem like a distant dream anymore.