Anyone with Rudy Project Rydons will know they certainly do not have a flat face on which to mount the Varia Vision baseplate.
This is a solution: http://www.thingiverse.com/thing:1474915
You can get this printed by a commercial 3D printer like shapeways if you don't otherwise have access to a 3D printer. It is tiny, so cannot cost much...
Hopes this helps someone...
cheers
Rod in Oz