So to preview - what you're looking at here is the front of surfyak from forms 3-8, the strongback laid on its side, 2"x1/2" spacers on ea side and a pair of wedges for ea form.

Now outboard of the strongback are 2 @ 1/2"diam holes (w/ bullseyes) drilled and marked in exactly the same location in each possible form. With braided nylon string pulled tight (I get a note), you can see how easy it is to line up each form to a string width. Even in this photo from 4 feet away, you can see form 5 is offset by a string's width (1/32" or so). It's also appears offset by the same amount on the other side so all's well! (good enough for me - prob caused by paper shrinkage or bad glue up job).

If you happen to do this yourself:

1/ put the wedges on the opposite side to the form drawing (I forgot) so you can see all your marks on the form.

2/ drill the holes up higher so their centrelines are over the strongback so you can sight from one to the other. (surfyak is too rockered for this)

I'll put up photo 3 tomorrow - Strongback/Sawhorse Idea

-mick