I have a 1977 35hp Johnson on a 1448 aluminum flat. 12 gallons gas, two batteries,trolling motor, 1/2" plywood floor, 300 pounds people. With Solas aluminum prop 10.5X11 max wot 5780 rpms 25 mph hardline tach.. Bought a new Solas Saturn 10.5x11 stainless prop. With new prop max wot rpms are 6030 rpms 27.2 mph gps. Prop performs well at all ranges. Need advice to lower wot rpms . Would cupping do this or would repitch be better?