Okay so I found a 45% combo midscreen for 1 meter that seems to work on every character, even if you have to be very close to the opponent, it can be useful! Oh and it ONLY works midscreen, in the corner b3 (or even f3) won't connect because you're too close to the opponent.
3 xx mass toss mb up shoulder, b3, j2, 123 xx mace charge 45%
It can be improved by replacing the j2 with a j3 and adding a f1 right before the mace charge, but it's much more difficult to do.
By adding f1 the combo will do 46%. By adding both j3 and f1 the combo will probably do something like 49%. I only managed to land the j3 123 once, failed landing the f1 though so I can't be sure.
I recorded it without the F1 at the end, 45% damages is the most practical version.