I wouldn't mess with the prop, throw out a drift sock or use your bowmount trolling motor for low speed trolling.
I have a 50 hp 4 stoke on my 17' deep vee that is rated for a 90 hp max. I'm not a speed demon on the water and it does just fine for me!
One thing you may want to consider on getting up on plane faster is your motor tilt, tilted all the way down for getting up on plane... then tilt it up after it gets up on plane for more speed.