I am wanting to purchase a spare prop for my 2008 9.9 mercury pro kicker. The existing prop is a 4 blade prop that is designed for trolling. I have been told by 2 dealers that the only prop that will fit is the factory 4 blade prop. Is it possible to replace prop with a 3 blade prop. When I search for replacement props it gives me 4 different quicksilver props. (different pitches 8,9,10,11 1/2 ) Who is right? What pitch would be an all round good performance choice?