Waiting for a solution as you are ... There are differences in the dimensions of the bodies so we will have to wait and see. Can't wait to pick my R5MK2 tomorrow !.
The Really Right Stuff L bracket for the body of the R5 and R6 (BEOSR5-L) fits the R5 Mk II. The ventilation holes on the bottom of the camera body are slightly blocked. If I had to guess: 20-30% is blocked.
A small part of corner of the rubber flap covering the HDMI port is on the side blocked, but the rubber flap can be opened.
The Really Right Stuff L bracket for the body + BG-R10 grip of the R5 and R6 (BGR10-L) fits the R5 Mk II with the BG-R10 grip as well. I'm still waiting for my BG-R20 grip and will update when I have got the new grip.
Edit: the Really Right Stuff BGR10-L L-bracket fits the R5 Mk II with the BG-R20 grip.
For both L-brackets: I have not verified the alignment marks for panorama's (yet).
I just heard back from Smallrig and they do -not- have an L-bracket for the R5m2 ... yet. They are hoping to
release/announce something in September. I have no info from other possible sources.
Hi ... I got the Wimberley head intended for use on a monopod. Arca mount. Camera mounts to it in a
vertical position but that can be fixed with an L-bracket or cage. But I found that it didn't really want to
hold the weight of the camera (R5m2) plus lens (100-500). I had to really reef on the locking device to
get it to hold it without "folding" (drooping towards the camera). After I had it screwed on tight
enough I found the camera being off center (not positioned directly over the monopod) to make for a
significantly different motion than you would get with a gimbal. I have yet to actually try it out to see if
that matters. I found the overall weight of the monopod plus the Wimberley to be ''probably OK".
Even with the camera plus lens ... as in far less than a tripod with a gimbal.
An L-bracket woud allow you to get the camera+lens over the monopod better. Right now I'm
using an Arca plate on the bottom of the camera.