I purchased the Boatmate wheels Diggs (pdxWAKE) was selling last year.
Trailer is an '01 SMP. Because out boat sits between the fenders, just bolting on a set of 10.75" and calling it a day wouldn't work...at all. Instead I had to widen the fenders with all the clearances being very close.
The inside carpeted board was already shot. I created a new one along with creating 1.5" of spacers to move the board further out. I then re-drilled the fender mounting points, moving them out to where they just clear the tires when the suspension compresses. Because the boat sits between the fenders, I now only have about 2" of clearance total...this is actually a good thing as SMP trailers are bad for getting a boat centered on the bunks and this actually helps a little bit.
I still need to makre some minor tweaks, as I have a bit of inside rubbing at full suspension compression - I just need to adjust them up a bit (tires are 1" taller than my 14's were) and move the port side inward slightly.