Thanks for yet another excellent and humorous writeup, Tony!

2 personal cents:
-Having the headstock trapezoid-shaped (rather than just box square) should (at least in my empirical theory) make it more stable,
and filling it with concrete will also add to that (apart of being over the top - but that goes without saying).

Q: -What about you workshops temp differences thru the year, combined with the "linear thermal expansion" of CI vs steel and concrete?
Any thoughts or hypotheses on that?

-Please keep up all your different projects and good spirits!

Cheers
Johan