Swallow UL 20/30

I say this as someone who has bought a lot of sleeping bags. It’s better to spend the money on something premium upfront. I bought a $100 then a $200 then a $300 sleeping bag… and still kept freezing my ass off. I now have a feathered friends swallow, and have no complaints. If I had just invested that money upfront, it would have saved me lots. Consider WM, FF, or pHdesigns for your next purchase. You won’t regret it

I worked at a man camp for one winter. Used a down 20 degree sleeping bag most of the time, but also had a second bag to double up when it dipped down lower. A sleeping bag is a lot warmer than a quilt. I slept through a few -20F nights without much issue. I had a lightweight Feathered Friends bag, but I recommend a heavier weight material for hard use if weight isn't an issue. I remember fixing a hole or two with some duct tape. I still use that same bag.

I'd been using a Marmot for 30 yrs, what they called a 10-20 30. Don't remember the price but it was the most expensive thing I bought for a very long time and glad I did. There were not as many choices back then and I don't think they are the same now. Point is it was annoying when it was warm. Couple of years ago I got a Feathered Friends Flicker 40. It's a hoodless sleeping bag that can also open all the way to a quilt. (no it doesn't attach to a pad) Had that down to mid 30's cowboy camping in the desert and was fine with a puffy on. I had wanted a 30 but out of stock. This year sold the 40 and got a 30 for a trip to Iceland in July. I'm very happy with it; works well across temps. Combined with the Marmot gets me down to 0. Since it is a bag when I want it's less fuss than a lot of the quilts out there. (love the draft collar and the foot closing completely). You can rent one and they will credit up to 2 nights rental cost toward a similar purchase. May help but likely incur some extra shipping costs unless you're in their area.

Feathered friends will customize bag sizes. At 950 fill power down they are as lightweight as you can reasonably get.

The ratings are not always reliable so you are right to be uncomfortable with them. One good baseline is ounces of down at the same fill power. Comparing bags that way gives you a better comparison point. Western Mountaineering and Feathered Friends are generally reliable in their ratings. That should give you an excellent place to start.

Feathered Friends will customize bags. They did it for me.

Western Mountaineering, Feathered Friends or Marmot for bags. Enlightened Equipment, Hammock Gear or Katabatic for backpacking quilts. Not cheap but quality and comfortable.

I've been a quilt user for years, but if I were looking for sleeping bags, I would go with either Western Mountaineering or Feathered Friends. You absolutely get what you pay for with either brand. Awesome quality.