Does the stock mp_autobalance work on spawns, or just rounds?
Anyways, I'm just starting to look at smm, but I do know es stuff, and you could take one of the team balancers and change it from doing the calculations at round end, and do them every x Player_deaths....
If no one around here can help yet, pop over there and ask one of them.
( not trying to support one system over another... just trying to find solutions!
)