I tested it as well, 7 shots is possible (just barely!) Barely is a good thing since it means we'll benefit from the attack interval reset at the tail end of it too.

The timing is so tight that I don't think it's possible to use it prepull at all, which means something like Hot Shot > Hypercharge might be the way forward.

That does leave the important question of how to amend our opener, since Potion used to be in that slot and there's no way you can activate both without clipping.