Yamaha 3-Cylinder on Express 1546VJ

[boben1968]

I have a 1997 1546VJ Express 6 gallon tank, trolling motor, loaded ice chest 2 people. I Just bought a 1999 Yamaha 25 3-cylnder. I have not ran motor yet. Stiiting on a jack plate1" above bottom of boat, set back 9-10". I have a new Power Tech 10 1/8 x 11P SRA prop. I thinking I need a 12P. Would this be a good place to start? I am going to run it this weekend loaded and check the RPM's with a tach and go from there. This boat weights over 300#. I think heavier than like a 1544 Weld Bilt. Any thoughts? Thanks..