This thread actually has two parts to it.
first of all, I have been looking for the lightest, 40 degree bag out there, and what I have come up with is the Nunatak arc Edge, and montbell UL thermal sheets. they both weigh in at about 12 oz. I have a Arc Ghost and Mont bell clo-up sheet (the synthetic version of the thermal sheets no longer made) I like both the bags but the Edge looks much smaler than the ghost. What would you recomend be the better bag for summer and fall use (with a cocoon jacket)? the thermal sheets are large, if they are the same size as my clo-up sheet, but have less down fill and lack the advantages of a variable girth bag. they would both be used in conjunction with a bivy sack. what do you think ? They both are rated at 40 degrees by Backpacker magazine. Whether they are accurate ratings, I dont know.
smaller Edge with more fill,
or the larger thermal sheets with less fill but more room for insulating clothing?
also, I looked at my Gear guide issue of backpacker magazine this morning and I saw 4 bags listed under bozeman mountain works.
a 39degree Sparc, 14oz/900 down
a 36degree cocoon, 15oz/polarguard Delta
a 33degree Catalysm 18oz/polarguard Delta
and a 30degree squall 180z/900 down
all the bags were listed as new, I have joined these forums after this magazine was published so I want to know if these bags were ever in production or if they may be up coming.
It confused me that they did not have tha Arc X bag, the only bag I knew BMW made

