okay, I've been way too busy. I finally got to take the boat out for just a little bit today.
So far by dropping down to the 19p, the boat is way more responsive. The throttle response is unlike any boat I have ever owned, I mean I feel like I added 100 hp to the back. It also lift the boat a lot more due to the higher rpm.
As of right now with approx 60 gal of fuel. Light load, just me.
4200 rpm= 37.8mph gps
WOT with 2 adults 60 gal of fuel, = 5300 rpm @ 47.4 mph
so all in all, in comparison to the 21p: way more responsive, faster planing, boat rides higher out of the water. I'm very happy with the 19 rev 4 and would recomend this prop!!!!!!!!!!