Here's a thought... I was always told a keel boat should rest about 50% on the keel and the ballance on the bunks or pads. When I first looked into Montgomery Boats I looked at Alina and the port bunk board was pushing into the hull enough to cause the hull to flex inward. After looking a several, I find that not all Center Boards are equal. What I mean is, some stick out of the slot more than others. On Alina, the board was out about 1/2" when all the way into the housing. That would effectively eliminate the possibility of the keel resting on a roller or shelf (would damage the CB or pivot pin). Others I've looked at, the CB is tucked into the keel housing very well and the keel would easily be able to support a good portion of the boat weight. I'm not to certain one size fits all when it comes to bunk boards and rollers on M-Boats. Maybe the hole drilled for the CB pivot pin is not "exact" in all boats of all years. If that's the case, it would be best to see what is there before commiting to one solution. There is one person who has added a third support to his bunks to help eliminate bunk board sag which had caused his CB to become damaged on the crossmember of the trailer. The jury is still out on this, but it is being watched as a possible alternative to CB damage from the trailer `crossmember on the "Trailrite" and maybe other trailers. Randy Graves has recently redone his Bunks and added a layer of closed cell foam under the carpet to help fit the lapstrake better. The idea came from a suggestion on the list. Randy is pleased with how the bunks came out and how the hull fits. Just thoughts Bill M-15 "Salty Lady" not ordered yet