I just used Rustoleum oil based paint with a banana roller. No primer just scuffed it with a green 2 inch pad and an air grinder and two coats. Did it about 10 years ago and still holding up fine. Allow about two weeks to dry.
The easiest prop protector I have read about is simple. A plastic cutting board mounted to the cavitation
plate on the motor and cut to shape to prevent the rudder eating prop from doing it's dastardly deed.:cool: