Going to a smaller prop will probably get you a better hole shot, but then bring down your top end at WOT. Usually there is a RPM range listed for every motor and I believe most are stamped on the motor somewhere. Basically says your motor should run within a set of RPM values.
We just went thru this last year for our 115. I think we tried about 5 different props, different diameters and different pitches. We finally found one that got to the desired rpm at WOT with a normal load ( 2 people, decent amount of gas and some fishing gear )
Usually the bigger the pitch = more top end, slower hole shot, smaller pitch = faster hole shot, less top end. 17" pitch say in 1 revolution, the boat should travel 17" forward, 16 pitch = 16" per revolution, etc.
I'm no expert, but like I said we just went thru the same situation last year. The Loadmaster has a number to guy in Superior that only works on Evinrudes, but can't remember the number. He helped with ours when we were finding the right prop. Nice guy and does excellent work. Call my dad at 218-428-5436 if you want the #.
Otherwise slap on the smaller prop and see what happens. good luck.