I had to go through the Timber Island drill a few years ago with a 33 Baja with HP500s and stock exhaust. Failed the first test at 84. Schedule the second test for a week later, but MP cancelled it due to fog and its effects on measurements. Still can't use the boat. Final test (and I'm not condoning this

), I stuffed my tips with steel wool. Had to do 3 passes. First was at 78, second was at 80 and third was at 84. Average 82 and a pass. Voila, no more steel wool, or should I say evidence. Only risk is creating too much back pressure, so it took a little trial and error.
BTW, saw your post on OSO. Great boat, great deal.