Jason, you may have misinterpreted what I wrote. I meant it as a POSITIVE thing. No money involved.
But, to be honest, expecting a small boat to be able to go WOT in rough conditions IS "user error". And, with lesser chop, you'd be able to use more up trim. Remember, you did mention that you initially didn't adjust the trim much.
If it was only windy, with little chop, you should have been able to turn 180* and go
faster. Unless the plug gaps were WAY out - which they didn't look to be - a small "out of gap" measurement would only have a minsule effect. I'm not sure what you mean by "tighten throttle cable". Was there an issue?
It doesn't sound like you need a different prop - you mentioned you had a pretty heavy load in the boat and still got almost what the Grady specs are. But that brings up another point... have you always had a heavy load in the boat? That's something to have mentioned early on since that can have a dramatic effect on WOT speed/RPM... again, user error, if you did
However, if you're going to be running with a heavy load most of the time - then, yes, go ahead and drop a couple inches. When you have a light load, just control throttle/trim so you don't over-rev.