Depending on your previous RPMs at WOT and engine rated RPM range, you may not have to do anything if you multiply your previous WOT RPMs x 0.84 and the result falls at or above your mid recommended range. Since you are in a toon which doesn't really plane out, you probably won't notice any performance differences due to the engine running with a 16% higher load at the lower WOT RPMs assuming the torque curve is in your favor, weather, water conditions, on and on.
If that turns out to be unsatisfactory then purchasing the exact same prop, mfgr. and model, multiplying your current pitch by .84 "should" get you back to where you were in RPMs and performance......but I'd try it like it is first...may be just right. Any time you change props other than as stated, its a crap shoot how well your rig will respond.
