Proof of concept
Here is my ED80 coupled to the mount with a 5kg counterweight. Both clamps here are totally loose and the OTA is balanced in the alt axis.
EASY!
If your mount has dumb RA & Dec drives, this mod does not affect their use, and you can use the drives to move the scope effortlessly too. Just remember that you will need to move both drives in this alt az mode. If you want to use the slow mo controls instead of the drives, just undo the clutches on both axis. Very easy
EDIT: It just occurred to me that the RA drive will always be on so always tracking, unless your drive system has a way to disable it.
Alex.