I was looking through the JRB website last night, hoping that the 8x8 tarp tent was gonna magically appear on the site, ready to order , when I noticed that both the JRB Stealth and the Shenandoah both use sewn through baffles instead of netting baffles like thicker quilts. Both quilts have a loft of 1.5" and are rated for 40-45* on the JRB website.
That started a spark of thought that turned into a 5 alarm brain fire that kept me up until about 2:00 am.
I also remembered that the Western Mountaineering Megalite and HighLite both use sewn through baffling. The Megalite is rated at 30* and has a 4" loft and the HighLite is rated at 35* and has a 3.5" loft. The loft measurements are probably for the total thickness of the bag, counting the top and bottom, so you are probably looking at about 1/2 the loft of just the top section of the quilt (2" for the ML and 1.5" for the HL).
I own the one-of-a-kind JRB ultra light Nest and No Sniveller and they have netting baffles that are 1.5" and I think Pan said they are rated at about 40*, but from my experience with these quilts, that temp rating is a little conservative.
My main question is at what temperature or loft does sewn through baffling become ineffective? At what point do you need to forget about sewn through baffles and switch to using netting baffles. Using sewn through baffles would be a pretty quick and easy way to make a 2.5 season quilt,IMHO.
Another question that came to mind about construction. Do you sew the baffles through the quilt first and then stuff with down or you you sew the edges of the quilt, try to evenly distribute the down and then sew the baffles? I guess sewing the baffles first would be the only way on insuring that the down is even in each baffle.