i have a 2005 yamaha f 60 4 stroke, book says 5000 to 6000 wot. i bought this boat with a beat up 4 blade 11.1 x 11. with it full of gas and gear, my 250 pound *ss and my fat buddy i run wot at 6000 rpm and 30 mph by my gps. so my question is, if i go to a 3 blade what size should i try or if i...