This sounds like a very worthy project.
Here is something that you might find useful in accurizing the McMaster blueprints (if you're wanting the sets as built
, rather than idealized). It is an odd feature of the bridge geometry that I discovered back in early '05 (and which was confirmed by Petri Blomqvist, independently, via photogrammetric analysis of set images). The dimensions are based on the scaled set drawings, but may be off by a small amount as the bridge itself had no dimensional callouts in any publicly available drawings. The proportions of the individual wedges, however, are quite real.
I wish you well in your endeavor.