I Just bought a 89 115hp Mariner 25inch. I am putting it on my 89 19ft Cuddy Bayliner. I live in Utah so my elevation to each lake can change drasticly. What prop size and pitch is going to be the best for my boat? I fish alot but also do some water sports. I would rather be concervative and put less strain on the engine to make it last longer than get a faster speed. Can any one help? Also what is the best way to drain my fuel tank on the boat?