Louis, thank you for helping me sort this out! With your advice I doubled my top speed. I can go 14 mph! I removed the in tank filter and installed an inline filter. I tilted the motor down to get more up thrust on the stern. I made an extension for the tiller so I can move forward to plane off. For safety I tied a piece of string to the throttle handle so I can reduce speed if I'm in the middle of the boat. Once I get up on plane I can move aft and still go 10 or 11. The cavitation plate is about 1.5" below the bottom surface of the boat so that's probably a big part of my trouble. But I now I know the Wizard is capable of much more than I was getting. I still have a problem with the engine stalling at full throttle, but I will start another thread for that.
I'm really happy with my Wizard now, it's fun and exciting to ride now. Thanks for the guidance. When you double your top speed it's a good day!