Before you spend one penny spend some time understanding the bag. You are looking at a system of INSULATION which means trapping warm air. The colder the outside temperature the warmer, and therefor bulkier ( aka loft) the system. Now take this basic rule and demand it compress into a small package for carrying. You could A. vacume compress it, which is very expensive and good for one carry B. reduce the loft with claims of some secret discovery or interpretation of insulation. If you do either, there is another real world problem, that of how well and fast your insulation regains it's full loft and performance after compression. Now add to this your personal statement of large body size and we have the classic conundrum the industry is only to willing to 'solve' with exaggerated claims and voodoo science. Shelter may be the most vital item in your kit, More vital than fire making or a knife in many scenarios. You wouldn't carry paper matches and a Rambo knockoff, why shortchange yourself on a bag? I laugh at people who moan over a few extra pounds or cubic inches in a modern bag. Have you ever seen a photo of a real 19th century cowboy bedroll, not the doormat canvas tied onto moviestar horses? The monsters required a seperate wagon or a dedicated pack horse just for the bag! A good website to sort through all of this is www.wiggys.com