Hyperion 20F/-6C Sleeping Bag

I've been using a 19oz Thermarest Hyperion 20\* (which is only comfortable down to 32\*) with a 5oz Cocoon silk, but need to lighten my load so I can carry 22lbs of water (ugh!!) on a 3-day desert trip (it's worth it, believe me - the Mojave's mountain ranges are spectacular, especially in wildflower season). It looks like nighttime lows may only get down to 40F, so I can skip the Cocoon to save 5oz, but can I do better with a lighter bag or quilt + the Cocoon? Also, I'm hard on my gear (as is the desert), so nervous about bags with 7D fabric like Zpacks. I had a Montbell UL jacket with 7D shell and, while it was great, it lost a lot of down out of the many micro holes.

Just for future folks; my system is below and works well enough for me in winter snowshoe camping in the PNW. I have the [Thermarest Hyperion 20f ](https://www.outdoorgearlab.com/reviews/camping-and-hiking/ultralight-sleeping-bag/therm-a-rest-hyperion-20)@ 21.4oz ($550 USD) and a [Thermarest Neoair Xtherm](https://www.outdoorgearlab.com/reviews/camping-and-hiking/sleeping-pad/therm-a-rest-neoair-xtherm-nxt) @ 15.5oz ($230 USD) so call it 1046g's. R-Value of 6.9 combined with 20f on the Hyperion really does me well. Combined with some Alpha long underwear etc. and I can handle some deep cold temp's.

Sea to Summit Spark, or therm a rest Hyperion. Both just a bit bigger then a nalgene bottle when it is packed down

So very many choices. I've always found [Outdoor Gear Lab](https://www.outdoorgearlab.com/topics/camping-and-hiking/best-backpacking-sleeping-bag), as well as [Switchback Travel](https://www.switchbacktravel.com/best-backpacking-sleeping-bags) give some of the most honest, accurate comparisons. I may not agree 100%, but I mostly do, and when I don't, it's for minor reasons. Plus, they don't accept ads, and aren't "influencers". In fact, they buy all the gear themselves! You need to ask yourself some questions though: * How light do you need it? Are you willing to pay another $100 to shave maybe 2 ounces? * How much room do you need? Some are fairly snug mummy bags (MH Phantom, Thermarest Hyperion), some are more roomy (an REI Magma 15 comes in a wide, for example). * Do you like a lot of features? A Nemo Disco has "thermo gills" which help regulate temp, plus a nice draft collar, plus are roomy...all of which comes at a cost in it weighs more. * Still not enough room? Try a quilt. But quilts down below about 20 degree ratings don't make much sense. * Presuming you go down (recommended) most spray their shells with DWR. Some also treat the down (Sea to Summit, Thermarest, others) some don't by purpose (Feathered Friends, Enlightened), but you can do it on your own washing the bag in Nikwax Down Proof, or spraying it with TX Direct. Some bags even have GoreTex shells for extreme conditions. As you can see, it goes on and on. You could go down a real rabbit hole.