Dear David,
as far as I know, Wurlitzer did not build the manuals by themselves, but purchased them instead (and modified some to 2nd touch). Therefor you can stick to the actual AGO specification (e.g. https://wicksorgan.com/wp-content/uploads/2020/01/agoconsole.pdf [Note that the dimension 29 1/2´´ should refer to the distance between pedal and the FIRST manual.]), which foots on the ideas of E.M. Skinner. In Wurlitzer consoles (with 3 or 4 manuals) the manuals are inclined by 2.5 degrees towards each other - the second manual is horizontal. The FATAR keyboard stacks (i.e. manuals with brackets at their sides) are close to this specification when you tilt the whole stack by 2.5 degrees away from you (which is an easy task). Since the MIDI parts are compatible to FATAR manuals this guarantees to connect them easily by common electric plugs.
It gets more complicated to arrangeme (many) thumb pistons and to add 2nd touch.
I have built a Wurlitzer console at my home, so I have thought these things over already. Since such details might not be of interest for the majority on this forum, I offer you to contect me privately (via PM).
Best regards,
Frank