Actually this is a good idea, as an umpire I can say the absolute, without a doubt, biggest waste of time is between innings.my suggestion is 3 innings with 7 outs per inning=
please try to play 3inning with 7 out per inning total out 21. You will have
more grouders
more fly ball
more runners challenging the defense
more pitching to batters
more batters facing pitchers
more catchers throwing
more hits
more plays
in less time