David,
Have you tried the Dry Bunk Roller spray available at West Marine? When I put the new carpets on my bunks I could not believe how easy the boat moved on the bunks. I kid you not, last time I loaded the boat, it was not quite centered between the load guide bunks, I was able to slide the 22 on the bunks up at the wash rack. I did have to use a bit of the shoulder though. Never would have happened without the spray. (I used to move my Monty 15 on a bunk trailer all the time to get it centered on the trailer.
Harvey
SleepyC