In reply to James Gordon:
I spent 3 weeks in a crux single skin in Patagonia back in 2020. (Free loan from crux, had to give it back after - no chance I'll ever get any kit of them again so this is as unbiassed as I can be).
Pros: very stable and bombproof. Adequate length for 6". Fancy material that was surprisingly good at breathing....when it was dry outside.
Cons: in bad weather you get wet inside. Condensation runs down and pools in the base. I suspect mine might have had a slight leak at a seam but it was hard to tell. No porch, so it's either a 1 person (billed as 2), or your kit needs to stay outside. It was a bit scary to put the poles in as you had to flex them so hard.
It was an interesting experience to try something I was intrigued by, but mildly sceptical of - the whole "single skin" thing. I'm not convinced by it at all, except for some quite niche scenarios. If I did a lot of 2-3 day hits in, say, chamonix. Or himalayas stuff (but I think this particular crux was too much of a tent vs bivvy for that - better with a firstlight.) basically, I kind of think if you need a single skin, you'll already know it....
I thought I had notes from the time but can't see any. If I find them I might be able to add more.