re: overpropped vs underpropped
The math is the math, you would/should be able to over rev the engine, assuming your 3260 is under normal load. Personally, I would not change it unless it somehow voids the warranty.
You should never run at more than 3/4 throttle continuously, and at WOT never for sure more than your engine manufacturer specifies (usually less than 30 minutes).
If you are making hull speed, leave it be - if you are not making hull speed in reasonable wave action at 3/4 throttle then your engine is too small, IMHO.
Lessons learned are opportunities earned.