OK, so I installed the mast rotator last week and got to try it out this weekend. I have to say, it didn't have the downwind advantage that I thought it would, but I do believe it helped with a better sail shape. I really didn't let it loose down wind and only had it to tune the sail shape upwind. I did catch myself pulling on it downwind to get the mast to over rotate, though. Now, that gave a much better shape, but you have to hold it. I'm thinking about rigging some kind of bungee, but I don't know it that would fly.
Granted, the winds were in the 10-plus range, so the mast rotated on it's own. I think it will really help in the lighter stuff.
I had to grind off about 3/4 of an inch off of the mast base to get it to rotate. That left maybe a half-inch piece of metal sticking up. It looks funny, but it works.
The new 6:1 downhaul is very convenient, too. You can make micro adjustments and really crack off on the downhaul down wind with ease. It beats trying to recleat it like the old style. Being a 6:1, though, it makes for an additional long piece of string on the tramp.
I haven't done the outhaul, yet. I really don't see the need.