I just bought a Reinell 196FR with a OMC Cobra 5.0. Right now it has a new 15x17pitch prop but WOT is approaching 5000rpms at around 40mph. I'd like to get my rpms down in the 4200range at 45-50mph. I'm finding good deals on SS 14.5x19 props. Will loosing .5 inch diameter cancel out the increase in pitch? Should I go with a 21"? Also, will trim tabs help me get on plane sooner or should I go with a hydrofoil? Thanks.