i have 180 bumble bee bass boat with 175 johnson with a jackplate prop is a rengade131/2x25 4 blade runs great with one person still cant get the rpms up runs at 5500 around 60 to 64 mph with fishing buddy and his gear gets 55 mph at 5000-5200 holeshot is terrible,so questionis it fesible to have more cup put in the prop i have now or will it be betterto drop down a size?also a seen a prop on a yammy last night and it looked like the edges were cut off it was a ballistic i think whats the purpose in that?