how do i choose the best propeller for my regal commodore 28

Welcome to the Regal owners Forum! No vessel is "maintenance free"! Possible you can provide more info (in a salutation) what year, where docked/located, hours on engines, I/O's, V drives, etc. So, did boat get "on plane" when you first purchased it and now doesn't? What are engine RPM's at WOT (wide open throttle) ? Do you have out drive tucked in or out when pulling from start? Do you have trim tabs, and if so are they up (bow up) or down (bow down)? Maybe find a dock amte wit some experience to go thru these tings with you and let us know!

Good sailing!