Well, finally found some extra time yesterday to sew together the quilt I've been meaning to make for some time. I wanted something that would be a versatile bag, that I could use for all 3 seasons.
I decided to just sew my own, and went with Thru-Hikers kit. With 12oz of 900 fill down, I was expecting this to be good to at least 20 degrees.
Dimensions of the quilt when layed flat before stuffing was 84"x52"x40". At 6'0, I wanted to make sure that after the drawcord footbox was pulled tight, I would still have room to pull the quilt over my head.
Sewing was not too hard. I have to admit, the though of sewing a down quilt sounded hard at first, but a little reading went a long way, and I had no problems sewing. Baffles are tedious, but made a lot faster by the technique outlined here: http://www.youtube.com/watch?v=TQm2y3bQ9tg
Baffles were sewed to have a finished height of 2.25in, and stuffing was calculated at 2.75 in, making for roughly a 20% overstuff. Omni-tape is used for the footbox and head closures. Drawcords run through both the top and bottom.
I was very happy with how it turned out. When layed flat, loft is a whopping 3 inches in some places, although I would say in most places it is 2.5. This should get me to 20 degrees with no problem at all. I'm a warm sleeper, and I expect that with the proper pad, 15 degrees would not be out of reach with loft like that.
Finished weight is 18oz in the cuben stuff sack. It stuffs down to a ~14"X10" stuff sack quite easily, without compacting the down too much. I dont like the compression sacks that turn bags into rocks, I want this bag to last for a long time.
M50 is a great fabric, and once again makes me like it even more. A downproof fabric that weighs .69oz a yard is amazing. To top it all off, M50 is very very water resistant, which should help protect the bag even more. I probably could have used a little less down (9oz) and saved a few ounces on the finished weight, but I wanted something I could take earlier in the spring and late in the fall, and I figured if I could have one bag that could do it all, I'd prefer that over two different bags.
Finally, some pictures. I apologize beforehand for the bad quality of the pics, they are from my phone.