Here's the thread on the Club 20 I procured about a year ago. Similar kind of story, although the mansion mine came from is not quite at the same scale as Hudsonview!
http://www.videokarma.org/showthread.php?t=262402
I restored it and sold it (although I kept the reasonably OK 20BP4 for my RA-101 Westminster, where it is happily residing now). I'll contact the person I sold it to and see if he wants to provide measurements for the base, which the set has. Or he may be willing to post here.