Literature on wheel building stresses the importance of measuring "offset" on an existing wheel, and in the case of the crinkle design the splined end of the hub makes the most sensible datum. This is the same for all variants, the other side differs with the type of bearing cover or as on the unit models, the speedo drive.
One thing to remember is that even new wheels are never absolutely perfect, and an example used wheel may not be to factory spec anyway after years of use, abuse and spoke tightening. Makes sense to see how badly out of true any wheel is, before taking measurements from around the rim and taking a mean figure.
If rebuilding a wheel with a new rim at least this gives a starting point, again assuming the new rim matches the old exactly in profile but at the end point, Rex says it all, forget published data, just set the rim centrally in the frame, with bearings, spacers etc in place and the spindle tightened. Plunger frames do flex a little bit, but with the rear mudguard off, the bolt on the centre of the footrest forging makes a good central reference point.
Swarfy.