Not a Bassboat, but....

My buddy just bought a Tahoe deck boat. His wife wouldn't let him get a straight up bass boat. http://www.bassboatcentral.com/smileys/doh.gif Anyway, it is a Tahoe Q5I Fish and Ski with a 4.3 Litre multi port inj. motor. Any ideas which prop would help him get the best performance out of this rig?

I like the powertech 4 blade on that sled. Never going to be fast, but it can be quick....

Thanks Pat. He's running a 21 right now and only gets 4k rpms. He thinks he should be turning 4800, but I'm not sure he knows much about this motor. Should I suggest he try a 19"?