I have a cl that I need to do some work to in the arm department, hopefully tonight, wife willing, and I'll see if I can find a way to disable the arm without destroying anything, since the meter is not really that hard to fix.
Nag me via email or pm if I havent' replied here again soon..
Edit-
I just looked at the mechanism- it's gonna be pretty hard to do, if not impossible.
Take the lens off and look at the arm up in the corner where the pivot is-
See the black pin that is pointed towards the front of the camera on the arm? That pin moves up against the bigger pointed pin above it, and that action is what appears to fire the first curtain! -The arm triggers the shutter- So if you just take the arm off by some brutal means- no shutter!
I think all J12 owners have been in the same predicament- wanting to use the lens on things that can't take it; even the soviet bodies sometimes need the rf arm bent up a little to make enough clearance.. The best solution i've found is to get a fed2 body or even a zarya (viewfinder fed-2 variant with no rf- cute!) and use that instead.
Maybe I'm wrong about this, and there is some way to butcher the heart out of the CL and have it still fire, but no good way I can see.