NEMO - Forte

I vote for Nemo bags. I have 2 and love them. Perfect for side sleeping.

This. I hate mummy bags. I move too much in my sleep. My Nemo takes up a bit more space in my pack but it is so comfortable and a good night’s sleep, where I can fully roll around in my bag, is worth it. I will never go back to a mummy bag.

Nemo for sure

Spoon shape is great, arm zippers in the boost just seem drafty.

I’m a stomach/side sleeper and love my Zenbivy quilt+sheet and their matching pillow system, but it’s quite an investment for a casual camper. I’d recommend looking for a cheaper quilt or even a rectangular sleeping bag on Amazon or Decathlon if you’re not looking to spend a lot. I was really unhappy with my spoon shaped Nemo sleeping bag. Even though it’s wider than a traditional mummy bag, it was still restrictive. There are a lot of other spendy quilt brands out there and most have already been reviewed on r/ultralight.

I’ll be the dissenter - I hated my Nemo Forte 20 (W’s long). We’re the same height and around the same weight and I found it too narrow in the shoulders and despite the spoon shape, I could not rotisserie comfortably. I didn’t find it warm, either, and experienced huge cold spots down the side opposite the zipper on a 35° night. I replaced it on a whim with a Zenbivy core bed and love it. The sheet keeps the quilt in place while I spin and the pillow pocket lets me throw my arms up while keeping them covered. The quilt is wide at the top and can tuck around me like a regular comforter. Super warm too.

Ouch, you are in a tough situation. You need a small sleeping bag, but have a low budget. Basically anything you buy is going to take up half your backpack. Your tent and sleeping pad will most definitely need to be strapped to the outside of your pack. 35L pack is really a limiting factor. Sure - the Nemo Disco is a fine sleeping bag. Better than the Forte for sure. The Kelty Cosmic is popular because it's cheap. If you can afford more, like the Nemo - go with that. I'd skip the 'zip together' feature. Don't limit yourself in that way. It sounds cute - but in practice joining 2 bags is not comfortable / warm. At least over the 18 years I've been with my GF. Hard to say more without knowing what brands you have a pro deal with and what temperatures you'll need to use the sleeping bag in (temp rating 15/20/30/40F?)

Nemo sleeping bag with REI 2.5 self inflating sleeping pad works for me.

Never tried a quilt, but as a fellow side sleeper I LOVE my Nemo sleeping bag. Can't believe I ever tried to use a mummy bag.

If your biggest concern about a sleeping bag is room for your legs to move without feeling constricted, I would try out Nemo or Big Agnes sleeping bags. Both tend to have wider profiles. Definitely go for a bag that is rated at least 10 degrees lower - preferably lower - than the temps you expect to sleep in. Theres multiple problems with layering with clothing like this, one of which is not the warmth specific factor but the breathability. One or two layers is one thing, but with all the listed clothing and then something like the picture on top, you’re going to build up humidity near your body you can’t get rid of, and you’ll become even colder. Next, a sleeping bag basically creates a warm pocket of air around you. The insulation in the bag helps create and maintain this pocket. The more compressed this insulation, the worse it performs. With layering clothing, you compress the insulation, making it less effective. On top of that, insulation is minimal if not nonexistent at the seams. Some puffy jackets and “extreme temp” clothing gets around this by minimizing seams but there’s almost always a few somewhere, which means no air pockets and no warmth. If I could recommend the best case scenario for you, it would be this: find a sleeping bag you can tolerate rated to a temp appropriate for your conditions, 15F at a minimum, best scenario a 0F. Dress in only your smartwool layers, and make sure you have a good pad/sleep set up underneath you. Sources: avid outdoorsmen, backpacker in sub 20 degree temps, and former REI employee who specialized in camping gear.

Nemo Equipment men's and women's zip together and the Disco line (I think that's the one that's down, not synthetic) is very compressible. They're also spoon shaped for side sleepers. I have one that I'm not longer using since I went to quilt life. I have zipped the men's Disco with a women's Forte with zero issues at all! It's this one (https://www.rei.com/product/163032/nemo-disco-15-sleeping-bag-mens (Torch/Stormy Night) and if you're interested in buying, I'd be happy to list it on r/geartrade for you (to go through a slightly more vetted process). EDIT: added more info

I like the spoon shape of the Nemo bags. And, I’m currently using a wide deluxe pad from Big Agnes.