Scorpion+Scorpion average ~35-39% meterless depending on which ender and timing of hits/kameo:
f32, j12-air spear-neutral kameo (anti-air fireballs), standing 4-bf1, 33-ender. For enders I was experimenting with 33-bd3 (teleport, weakest but ends in restand with a great opening for throws or whatever), 33-bf2 (dash), and 33-db2 (chain spin). The last one did ~37 - 39% meterless midscreen.
Sorry if my notations are weird. Would likely work with some other kameos if you can get the timing right for the air juggle. Who knows. But good meterless damage.
Ending with 33-Fatal Blow did ~47% and I didn't even get the timing perfect for optimal dmg.