sometimes you can save yourself a lot of time, headache and heartache by asking someone first, just to get the gist before you submerge yourself in details
Indeed, that's why I posted my query here. And not just to get the gist before submerging myself in details, but even to find out where the details could be found to submerge in! Erik responded, but he understood that I was interested in joining an MDCG, which I'm not. I'm just interested in participating in "Rev 5." If joining an MDCG were possible and that was the way to participate in Rev 5, I'd consider joining one, but really would rather not get that drawn in, even if I could.
Anyway, he expressed his doubts, with which I concur, and by then Marcelo had given me enough info for me to dig my way through to the information on the CID working group, which is probably about as far as there is to go until they get further along in the transition. So I didn't pursue it further with Erik.
I also emailed the medical devices contact at Medsafe in New Zealand, but, realistically, I'm thinking at best I might be able to submit comments during an open consultation some day, if that's how that works.