
NEMO
Disco 15 Series
Spacious spoon shape, but bulky and inconsistent warmth.

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I have a Nemo Jam, which is shaped like the Disco. I'm a side sleeper and I absolutely love it. I don't think I could sleep in a mummy bag.
The Nemo spoon shaped bags, TR Boost or BA Torchlight are all nice and accommodating for flamingo type sleepers (I am one as well.) Also consider a quilt!
I’ve been backpacking with my Nemo 30 for about 4 years and I LOVE it. I’m a side sleeper and I toss and turn a lot and I find that it gives me (5’ 0”) plenty of room to move around without getting cold. On warmer nights, I just open the zip and get enough airflow to not overheat. It’s lightweight and packs down super well with the provided compressive bag. Generally speaking, I run warm, and have comfortably used this bag in temps well into the low 30s with wool base layers and not felt cold
i’m 5,3” and i have a women’s nemo bag that fits just right
I sleep like you and it’s been the bane of my backpacking experience for the last 40 or so years. A few years ago, my husband bought me a Nemo side sleeper sleeping bag for Christmas. I was a little skeptical, but it actually helps a lot. I can’t remember what it’s rated to. It’s definitely not for extremely cold nights, but I don’t know if there are options in that. For car camping one of the main things I do is carry a wider pad. That way when I pull my knee up into the side, it at least stays on the pad and isn’t on the cold hard ground. As someone else mentioned, I also keep some extra gear in a stuff sack, and use that underneath my knee, which helps for warmth and back comfort.
I like the Nemo sleeping bags that have the gills. You can open them when it's warmer and zip them up as the temperature drops. Works much better for me than just opening the side zipper, which I find let's too much heat out.
BLUF: Test fit at a store or use the 30 day return policy. Only you can determine what length you need as there are multiple factors that go into that. Cost is based off several things and comfort isn’t usually one of them. A few things. For determining length: Most camping stores or stores that sell sleeping bags will let you try them on at the store, plus there is usually a 30 day return window. I’ve noticed a difference in actual bag length both from the same brand and definitely between brands so doing a test fit is always beneficial. Finally, how do you sleep? Do you keep your feet at a 90* angle from your legs like you are when standing and measuring your height? Do you relax them or point them away from your head (some side and most stomach sleepers)? Do you put your “pillow” in the hood of the sleeping bag or leave it outside? Do you put your clothes in the bag with you to keep them warm for the next day? All of these things will determine what the right length of bag for you is while remembering that large unfilled space will require you to heat it or fill it. Bag temp should be based off of night time temperatures. Yes, you can use a colder rated bag when it’s warmer, but people often can’t figure out why they are cold in a 10-15* bag when it’s only in the mid 30s and think they need a 0* bag. Price could be due to better materials, insulation (lots of different qualities between the various “synthetic” insulations, type of down and it’s fill count), “compressibility”, brand, and quality of product. Finally, comfort is entirely subjective. Lighter is definitely better when you have to carry the sleeping bag; however, lighter may mean it’s a tighter mummy fit which may make you more comfortable or may make you less comfortable. As a side sleeper/rotator, while I could sleep in a mummy bag, once I tried the NEMO spoon shaped bags I started sleeping so much better and will now only rock a mummy when I’m really worried about weight or when the temps are in the low teens and below. Also, how noisy is the sleeping bag? How noisy is your sleeping pad and bag? And how does the sleeping bag slide on your pad? Some of the fabrics over the years have not only been very noisy, but also very slippery and both of those can cause issues. Once while on a week long backpacking trip, I was ready to kill my hiking buddy because his new sleeping pad was so F***ing loud that anytime he moved during the night it was like someone getting into a fight with a bag of chips and I would wake up. He also had the problem of the two fabrics being extremely slick and so if we were on anything but perfect level ground he was sliding downhill. Needless to say he never used that very nice and very expensive sleeping pad again.

NEMO
Disco 15 Series
Spacious spoon shape, but bulky and inconsistent warmth.
Hammock Gear
Classic Burrow 20°F
Budget-friendly quilt; very warm, but not ultralight.

NEMO
Disco 30
Roomy spoon shape, but bulky and prone to zipper snags.

Katabatic Gear
Alsek 22°F Quilt
Premium quality, very warm, but high price for weight.

Neve Gear
Waratah
Great warmth-to-weight and value, but untreated down.

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Kelty - Tru.Comfort Doublewide 20
Ranked #1
Enlightened Equipment - Revelation APEX

Ranked #1
NEMO - Disco 15 Series
Ranked #1
Hammock Gear - Classic Burrow 20°F

Ranked #1
NEMO - Disco 15 Series