
NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.

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https://www.nemoequipment.com/collections/womens-backpacking-sleeping-bags/products/disco-womens-endless-promise-down-sleeping-bag I've got the men's 15 version of this and like it a lot. Just used it over the weekend down to -3° C and was plenty toasty.
I have the nemo disco 15 in the big boy size. If you get cold easily, I'd recommend the little bit of extra bulk and weight for the 15. The spoon shape is much nicer than a mummy bag.
You could use a Paria quilt of you want to try that route. Saying that I just bought my wife a disco 15 and tried it. They are very nice and not claustrophobic at all.
If you’re having issues you could place the disco loose into the bag without the stuff sack, it allows it to contour to the space inside the bag more. Same with the hammock and underquilt. Then when you cram everything else in there it should compress it and make more room. If that sounds like a chaotic mess to you then at least just do it with the disco in the lower backpack compartment.
Get a disco 15 from Nemo. Only use kelty in the summers.
I love my Disco 15, it’s so warm and comfortable. Not the lightest option out there but I wouldn’t trade it for anything.

NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.
Hammock Gear
Classic Burrow 20°F
Budget king; very warm but heavier than ultralight.

NEMO
Disco 30
Spoon shape for side sleepers; prone to zipper issues.

Western Mountaineering
VersaLite
Durable, very warm; premium price, too hot in summer.

Katabatic Gear
Alsek 22°F Quilt
Versatile 3-season quilt; secure pad attachment, high price.

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NEMO - Disco 15 Series

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NEMO - Disco 15 Series

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NEMO - Disco 15 Series