There seems to be a point when sympathetic vibrations reinforce each other enough to become annoying. I just adjust the throttle enough so that the vibrations are minimized. Also, I understand that a two bladed prop like mine causes more vibration than a three bladed prop - not exactly sure why - has something to do with the way the tip interacts with the hull as it passes. In my case, I also do not think there is sufficient tip clearance with the hull (supposed to be something like 10 or 15 percent of the prop diameter) which also contributes to vibration. However, dimensions on the 32-3 are tight and I have already had my MaxProp reduced in diameter (by MaxProp) so there is nothing left to do (AFIK).