Im going back and forth to even see if its possible, I have held on, I know its about 14LBS but I also know the m15 can handle up to 20 if you really needed it. thoughts?!
L12" x W6" x H8" and 13lbs without lens or finder so depending on how your counter weight it since M15 depth is 7.87", you should be able to mount it without the top of the cage on and a light weight prime..