> The 40223 requires a double cable release 40142. The 40223 was available from 1968 to 1982. The 40517 uses a telescoping tube to connect the body to the lens through the bellows unit. It does not require the special cable release. It was introduced in 1979. I would get the 40517.
The auto bellows does not use a telescopic tube, but uses a simple, grooved, long, sprung axel, extending the full length of the bellows, tripped by the camera, and over which the front standard rides.
A bit sturdier than a telescopic tube. ;-)
The main difference, i feel, is that the automatic bellows extends in front of the lens, poking the subject, while the unused part of the non-auto bellows extends to the back, underneath the camera.
Depends on your personal photo-technique, but i find the "auto" part of the auto bellows rather superfluous. You must use both on a sturdy tripod anyway, and you must use camera prerelease and a cable release with both too.
Else, forget about sharp pictures.
You don't need a double cable release using the old, non-auto bellows. A single cable release will suffice. You will have to work in a large format camera style:
1) Use the cable release, attached to the front standard of the bellows, to close the lens shutter and diaphragm(not pushing it all the way).
2) Prerelease the camera, using the prerelease button on the right side of the body.
3) Wait for all vibrations to die away.
4) Expose by pushing the cable release all the way, releasing it after the exposure is completed.
5) Cycle the body: press the body's shutter release, and rewind the body/film.
6) Rewind the lens using the rewind knob on the bellows' front standard, opening the shutter and diaphragm.
And is not very different from how you would use the auto-bellows:
1) Obviously, the cable release is attached to the camera's release button, instead of the front standard.
2) The same: prerelease the camera, using the prerelease button on the right side of the body.
3) The same again: wait for all vibrations to die away.
4) Almost the same: expose by pushing the cable release, releasing it after the exposure is completed.
5) Again, almost the same: cycle the body, i.e. rewind the body/film.
6) The only real difference: there is no 6) when using the auto bellows.
I have both bellows, but almost exclusively use the old, non-auto one. And that is because the rail of the auto-bellows sticking out forwards is a real pain in the nether regions. You hardly ever can get close enough to your subject (distance dictated by magnification and focal length of lens used) without having to worry about the thing pushing the things away, disturbing the scene. And for the same reason, you can very well forget about using the auto-bellows at all when using special purpose, typically very short focal length, close-up lenses.