Gordon Porter reminded me that six bid was what he used for the hatrack flange. Made sense to me, so today I added two more bid to the four bid I placed yesterday. Certainly more substantial. I also laid out and placed the hard points for attaching the hatrack to the flange. No manual for this, so I decided on one screw for each ten degrees, which works out to around every two inches around the flange. Should be fine. Also, I worked out a process for semi mass production of stud mounts for adel clamps. Managed to make a dozen in an hour or so, and could have made two dozen in about another twenty minutes. This is a lot of time, but I'm happy with the final design.