Interesting, in my little cruck frame I have noticed the crucks have shrunk away from the ridge beam, in effect the rafters are holding the ridge up not the crucks. The crucks are spruce, and such, they tend to shrink a lot. It is configured similar to the one Dave referenced. Now if the walls were to spread via the thrust of the rafters the ridge would then settle back onto the crucks, I hope that does not happen.