Backcountry Bed 20 Duo

In my experience one bag will never cut it. I have a summer bag good to maybe zero C. (It's Sierra Design's backcountry bed, and I fucking love it.) It's also comfy and not too hot for summer use. Then I have a winter bag I've used down to -26 with a liner. In true winter/arctic conditions I'd want a very good sleeping bag. Lol. So my advice: get a comfy light one for summer/light shoulder seasons, and one for the rest of the shoulder season. Otherwise I think you'd be sacrificing too much with the compromise.

I sleep the same way and mummy bags drive me nuts. For the last decade or so I've used the Sierra Designs Backcountry Bed. It's a quilt-bag hybrid made for stomach and side sleepers. Not the lightest but it was a game changer for me and I sleep just as well camping as at home now.

I found the Sierra Designs Cloud 20 and Backcountry Bed to be a unique fit for my needs. Wasn’t ready to jump into the quilts yet, but these have a hybrid with being a zipperless mummy bag. Also has a pad sleeve and slot to slip your feet out. These solved my problem of getting twisted up, on top of the zipper trying to zip up, or too hot or with hot feet. Cloud 20 is a little lighter/compact but is not as great if you face left in your right side. Both compact to about the size of a volleyball.

This was going to be my recommendation. Own one and it's great for tossing and tuning.

Sierra Designs has or had one recently. I tried it out but didn't like it much and ended up going with a Zenbivy which is exactly what I hoped it would be.

I also got an EE quilt and have thoughts on rating - I opted for a 0° bag but this was motivated by spending some uncomfortable nights right around 35° in my Sierra Designs down bag that was rated at that. With a quilt the zero seems overkill but the design has meant I've been comfortable in much warmer temps despite being a warm sleeper generally. I can open it up, hang a leg or arm out, or be just partially covered. They key with the quilt style is having a pad that is matched for the temps you're in. On my last trip i still took my Sierra Designs bag as it packs slightly smaller than my ee quilt but this setup works for me to cover a wide range of temps. Admittedly I missed the mobility of the quilt compared to the mummy but I've spent most of the last 30 years in mummy bags so it's not unfamiliar.