this looks perfect. thank you!!!
One point to note - with the plate installed and the foot mounted on the adapter, the adapter cannot
be mounted on (or unmounted from) the EOS M. You need to loosen the knurled knob on foot - not the plate, just the foot, and just loose, no need to remove it. With everything tightened, the plate doesn't quite clear the corner of the M.
A good reason to want to limit what you are carrying, but I don't think I'd be comfortable hanging my 70-200/2.8 off of the EOS-M adapter. I have not tried it, however.
Of course, with a ballhead less robust than the RRS BH-55 LR, it's quite likely you'd see settling and drift with a front-heavy load like that (and carrying a more robust ballhead just save on the weight of the tripod collar likely isn't the best choice).