I'm using Poser 4, and I never could get alternateGeom to work for props including the dial-a-prop. I'd sugest using a figure. The classic example of using alternateGeom is the hands in the "Skeleton Woman.cr2", the relevent parts in the hands are the alternateGeom statments, and the channel for the dial to swap the geometry "geomChan handGeom". It does not matter if the obj files have differing numbers of vertices.