The anchor is 2 pieces of 5/8" plywood separated by 3/4" pine.   A pipe clamp (metal strap with screw tighter) is used to tie the anchor around the pole.  Rubber grummet makes a nice mesh between the wood and column.    

There was no official work session on Dec 22.  At least not a session for the whole group, as I was attending my niece's 8th birthday.  However, I was taking the day off, to start my holiday's early.  To celebrate, Paul joined me for an early work session.  My original intent was to put up the final door (backdrop support), but Paul and I concluded that the layout needed to be anchored into the house (to the column) before the backdrop support could be completed.  Basically, since the backdrops on the peninsula are to be connected to the ceiling, the peninsula needed to be anchored into the basement so that it did not move.

On Jim Stewart's layout, we used a 4" U bolt to clamp the layout to the column.  The U bolt worked great, but my column's are 5" in diameter (my house was built back in 1936).  We could not locate a source of 5" U bolts.  Don Rigling suggested getting metal strapping and pulling it tight around the pole and using screws to hold it in place.  Paul went one better is suggested pipe clamps, these are strapping with a screw that tightens the strapping.  At home depot, we located an 8-12" diameter clamp in the heating and ductwork department (the plumbing department only had 1-5" diameter clamps).  Upon our return, Paul constructed the wonderful anchor seen in the photos.  Hopefully, the photos tell the story.

Here is a side view of the anchor.  The screw that tightens the clam is just visible between the plywood pieces (center of photo).  The screw is safely hidden from view and bumping. 

 
When the layout sections are placed on the benchwork, the anchor is nearly hidden, not obtrusive to the layout space.

While Paul was working on the anchor, I worked on the backdrop supports.  Specifically the anchoring of the doors into the ceiling.  Actually, the doors are not attached to the ceiling, they are attached to 2x3" boards which are wedged between the beam (house beam) and wall.  The span is about 14', so it takes two 8' boards to span the gap, and those board are spliced above the backdrop.

Why not attach the backdrops to the ceiling?  Because I plan to move, so I want to minimally impact the house, specifically the finished ceilings.  Additionally, I want to add support for valances and lights.  So the 2x3's will provide support for the valances, lights, and backdrops (keep the backdrops vertical).  In turn, the backdrops provide support for the 2x3's  See photos below...In the end, the layout is shimmed/wedged into the house, only a minimal number of screws lock it into place.

This photos shows one of the 2x3's as it meets the wall.  The beam was shimmed off the wall framework, and a screw was driven up from the bottom to lock the beam in at the wall.

Here the beam (photo above) is spliced to a second beam.  Notice the splice plate sits on top of the door (backdrop support).  Glue and 2 screws and a few shims are all that was needed to wedge the beams in place.

Here is the second 2x3" where it hits the beam of the house.  You will see one 4" screw into a floor joist.  I made this concession, to hold the 2x3" in place at this end.  If I were to do it again, I would cut 2 pieces of plywood to fit the contour of the I beam, and attach them to the end of the 2x3, so as to hold the 2x3 in place without a screw (I still may do it, as I'm not confident that I hit a joist with the screw, hard to tell in an old plaster ceiling).