I use the dimensions from my JRB No Sniveler (78"x48"; used w/a HH ULBA) for a base and go from there; just base your dimensions on your need for coverage (I'm 5'10" and like a 62" shoulder width) and/or the materials you use. For example: I modified a Sportsman's Guide ultralight sleeping bag into an under quilt/top quilt (48"x70")by eliminating the zipper, relocating one of the two top drawstrings to the bottom, and adding end and side grosgrain tabs for hanging loops and side pullouts. Bam! A 22 oz sleeping bag became a 16 oz quilt! I also took a ThermoLite poncho liner, cut it down, added a head slot and ended up with a top quilt/serape (72"x54"; 28oz to 22oz.), in camo no less (FishBone winks at Neo)! A pending project is to add 1.1oz ripstop wings to my JRB to use for sleeping on that "other" place hangers sometimes use when absolutely necesssary. This will expand the "wrap" from 48" to 62" and only add about 1-2oz. I hope that helps.