Caleb, I use a 5×8 Silnylon Tarp by integral designs ($75). It weighs 6.5 oz. I sleep inside a MLD superlight bivy, also 6.5 oz. Inside that I use a Golite Ultra 20 Sleeping quilt at 19 oz. I sleep on top of a Gossemar Gear 3/8" sleeping pad trimmed to 38" and weighs 3.45 oz. I have used this setup down to 20 degrees and used it in substantial rain. If money were no object I would get a MLD grace solo in spectralite and I would get a Nunatak Arc Alpinist quilt. Also another great value choice for a quilt is Jack-R-Better no-sniveller.
The GG spintwinn is a nice option too. I tend to prefer small tarps because I dont spend much time in my tarp. I crawl in at night, sleep then wake up and cook breakfast at the opening. Smaller tarps also fit into smaller places and shed wind easily. I could not fit another person under my tarp nor be comfortable spending much time in it…that is where a Spintwinn will shine.
On down vs synthetic…high loft down (800 or 850+) will always outperform synthetic quilts as long as they are dry. Many synthetics have minimal loft and really must be used with other insulating garmets for them to go to low temps. They are great if your gear is likely to get wet, but if you are looking for warmth per ounce of weight then down is the way to go.
If you want a traditional sleeping bad then check out Western Mountaineering or the ultralight Marmot bags (i.e. the expenside Marmot bags…hydrogen & helium).
Jamie
