Jeff, the 23" 2-blade bronze was sold to Ross to keep his RPM's under 5,000, but he can go at least 5,200 with that prop and it was the fastest on White Bear Lake of the three props tested at 48.3 MPH if I remember correctly.
Gregg, candidate props I have are the 21" three blade Ballistic stainless steel, and the 2-blade bronze 21" pitch Quicksilver. I have three props untried that I am saving for the 1988 115 HP Merc - 22" Chopper, 22" Ballistic, and a 21" PowerTec RAF.
You might try a 22" Laser II that would drop your RPM's down about 400 RPM, and after trying both the 20" and 22" Laser II on my boat, the 22" seems more efficient. Once my new motor is installed, I know of someone who has a 22" Laser that I may borrow. His boat is a Bayliner. There I said the "B" word. He left his boat uncovered in the winter and brought it over to work to unthaw for one week.
Glad you got in the test run. Makes it easier to know where to go from there. If your prop blades need filing, sanding and polishing, let me know.