Berry, my 90 is an older model so I may have to use the 20" to make up for its age and different design. I was very disappointed that I couldn't turn the 22" any faster. If you read this board and other Bass Boat Boards you will find the 22" Laser 2 is the ticket for a 90 on a lite boat. You will also find speeds posted in the 49 - 51mph range that I have never seen. At 5,000 rpm my speed is 43.8 mph. When I do performance analysis I use a GPS and have the boat loaded the way I actually use it. (i.e. 1/2 tank, all three batteries onboard, rods, reels, anchor, trolling motor, minnow bucket etc.) From what I've learned the goal is to select a prop that will peg max rpm at wot in conditions you would normally use it. It's better to slightly under prop it than over prop it. How much longer do you have to complete your break-in before you can determine your max rpm?