I saw where OWFINC carries Climashield in 3.3 oz, 6.0 oz, 9.4 oz., and 11.7 oz. I was not sure how the 3.3 compared to the 2.5 or how these weights compared to what Thru-Hiker sells in 5 oz., whether it was directly proportional in terms of weight and insulating ability or what.
I might reconsider primaloft. Even though it would require quilting for the filling to not shift around I imagine it would just be a quick and easy "sewn through" quilting, still tons easier than sewing baffles and working with down for insulation.
If I am looking at their specs correctly at http://www.owfinc.com/Fabrics/insulation.asp - it weighs 1.8 oz per yard and lofts 1/4" - 3/8"? I am assuming for a summer quilt I would still want to double it up for 1 to 1.5 inches of loft total?
*edit oops I just see where Thru-Hiker has it in 3 oz and 6 oz. Probably easier and cheaper than doubling a lighter weight up.