Hi,
I have just measured on 4 different radios, including the VBC.
I measure outer diameters of 44.6 to 47.3 mm and a possible deflection of the axis right at the root of the stick of 10-11 mm.
The radius of the inner hole will also be affected by the vertical offset from the stick's axis and the shape and maybe adjusted length of the stick, so it would be a stroke of luck to find one that fits exactly.
Of course you can calibrate the sticks again to allow for a different inner hole diameter if it's smaller than the maximum deflection.
Doesn't need to be plywood
you could also make one of delrin or acrylic glass or a glass fiber plate, for example.
I even tapered the inner hole so the stick would run on a smooth surface.
But in the end I found I hardly ever touched it irl, and the electronic cyclic limiter ring (or double truncated cone, to be precise) does it's job both for keeping the feel of the swash plate geometric if you do, and to prevent the mechanics from binding if used for that purpose.
Kind regards
Eddi
Born to fly ...
forced to work.