I contacted Albert a few years back and we discussed this very topic. Even with his design he said to expect a small amount of flexure. I purchased my altitude bearings from Dave Kriege and since they're aluminum I think I can fabricate a rather simple extension strut that would attach to the bearing and help brace the lower tube further up toward the focuser panel. I could also go for thicker walled tubing but then I run into a weight trade-off. I may just have to bite the bullet and start experimenting.
-------------------- Dale Burkhardt
18" homebrew dob with f/4.5 Torus-OMI mirror
Argo/Navis, ServoCAT
100mm Orion SVP w/Moonlite focuser
Customized SVP mount w/Sky Commander