In my worst dreams I never considered using a strong back as
a reference point.

I'm sure a strong back can be used as reference, but in case something
moves there will not be an indication for it, & I'll get a banana.

to my opinion the risk is too big.

I would use 2 small holes on each form, with 2 threads running thru
these holes. If something moves, at least one of the threads will touch
the edge of a hole.

you know, just the regular way, like you do on any stripper.

in the past someone brought up the idea of using a little laser
designator instead of the thread.

in his book Putz uses a flat floor as a reference. my personal opinion is
that this way is not accurate enough, & can't be compensated.

I don't have the book in front of me, but I remember trying to figure
out how to mark the exact location of these reference holes on each form,
& I was able to do it. no big deal.

good luck everybody,

Erez