Finding right prop for 20' seacraft.

[syxx]

We're finishing my 1977 20' seacraft and I'm trying to find the right prop for it. We've put a new floor in, well, console, filled transom in, and put a hermco bracket on the back with a jackplate. The bracket is 24" setback and the jackplate is another 6" to give full tilt for engine. Engine is a 150 4 stroke yamaha. Nobody I've talked to really knows what kind of prop to put on given all the modifications to the boat, any ideas out there?

Thanks,

Rick