Hey All, I need some help. I bought an center console, aluminum tunnel hull to fish from. It has a 70hp Yamaha 2 stroke with a 13 3/8 x 15 aluminum 4 blade prop. I am at 5100 rpm @ WOT. I would like to get 6000rpm and of coarse more speed. I want to change over to a 3 blade stainless but not sure what size to get. What are your thoughts?