[bojan]

I changed a concept slightly....
Adapter is still clip-on but to M42-EOS adapter.
The position of the filter relative to sensor is the same as conventional clip-mount, but the filter is attached to the lens/scope.
This way I have more flexibility in use of modified or unmodified or any camera in combination with any lens/telescope I have (all of them have M42-EOS adapter).
This adapter is easier to print with lower tolerances (0.1mm layer thickness, 85% infill, printing took 16 minutes) and the fit inside camera is better, it is tight but the elasticity of the material is sufficient to ensure self alignment.
Now I need a clear, light-polluted sky to test the whole thing, it seems Melbourne will be blessed with all that tomorrow.
Please note, the adapter ring is not solid, I made a cut (visible on the image at the away side of the adapter) so it could be widened to accept the filter.