Just finalizing my purchase of a Tohatsu 90 by negotiating with Marita for a SS prop (part of the deal). Currently running a 13.5x15 aluminum, which gives me 5000 rpm @WOT. So I want to step down pitch to hit 5200-5800 spec RPM, yes? Pushing a 19' Searunner. Any of you smart folks have a reccomendation for pitch and brand? 3 vs 4 blade a big factor?