It shouldn't be an insurmountable problem. to adapt the way you want.
If the Canham board clears the hardware on the Linhof.
A simple spacer between the boards is all that's needed. The Linhof board on the rear, spacer and Canham board. Sa cowanw says you do need room for the board retaining hardware so either the spacer has to be thick enough to allow for it or relieved for access.
The spacer can be aircraft plywood from the local hobby/craft shop.
If you have several of one size shutter make the sandwich permanent & swap shutter/lenses. Personally I'd make the Linhof/ply permanent & mount threaded inserts into the ply so you could use small(!) thumbscrews to attach the Canham board. The Canham would have to have holes for the screws drilled but a plug could be used if you want to go back to the Canham camera.

Try checking it out with foam core and double faced tape, it's fully reversible.