Is it possible to change the 4 rounds/3 min format?. why not let them fight for 20 minutes without any scheduled interruption, most submission wins? If there is no submission during the first 20 minutes, let the match continue until one submits or stop it and declare a draw after a prudential time (5 or 10 minutes more), if no submissions.
Alternatively, 4 rounds of 5 minutes each would also be fine.
what do you think?