Mike, noteworthy maybe is that I've found the big 4 strokes don't always perform best running at red line/max rpm. I have a fairly light 24' pontoon with a 90 Honda on it - has the same 6k max rated rpm. I set it up to turn that rpm, but ended up just slightly over at 6100-6150 with just me on it. Incredible hole shot, and mid range was near instantaneous. Top speed (26mph) came quickly. Great for pulling the kids around on a tube.
On a hunch, I went from a 13"p prop to a 15" to see what would happen (found a deal on the prop!). This dropped my top rpms to 5500. Nothing scientific to base it on, but I don't feel I lost any low end performance, or mid range. Now it will accelerate quickly to 22mph or so, and is a mile an hour faster, but does take noticeably longer to get to max rpm. Bonus is the engine seems to be running noticeably quieter.
So if you need max acceleration to top speed then set it up to turn max rated. Otherwise, consider shooting for -500 rpm or so, maybe pick up some speed, and loose some noise.
Had very similar results when setting up a Honda 50 for a buddy not too long ago. It liked 5500 much better than 6k as well. FWIW...
