Alas, I had a senior moment when describing my stack installation
procedure.  Where I used the term "thumbscrew" I had intended to say
"wing nut".  For those of you that experienced mental anguish trying
to visualize my scheme, I am truly sorry.

The wing nuts work quite well, and can be given a quick spin to rapidly
adjust the support point on the rod.

Sorry again for my misspeak.

Bob Taylor