On a previous post on this subject I floated the idea of using aluminum curtain wall track as a strongback. Many sizes but 2"x3" or x4" or x6" are fairly available. The huge kicker is that there is a continuous (continuous) threaded track down the 2" edge that is used to clamp the windows in place. Obviously strong as hell for wind and dead loads for hirises.

But the continuous track - It would be fairly easy to mount one on the opposite side of the section so you would get good purchase. So you could mount your forms anywhere and with rapidity and quickly slide them off for your new design. There also are inserts to allow for expansion that I bet would be good for making breakdown strongbacks or of changeable lengths.

I would sure like to know if there are any window guys out there to confirm whether this idea would float. But if it did, the speed and flexibility would be supreme.

-mick