Update on double quilts: I've got not one but two double quilt designs finalised, a UL version and a deluxe version (still a little lighter than two equivalent single quilts). In playing with the design over quite a number of months I figured that there would be room for two designs that would better cover the differing needs and priorities of potential users. I also wanted to offer an opening footbox version of a double quilt as it's a very nice feature to be able to open it up as a blanket and makes the design more versatile in use. I'm also looking at offering a sewn footbox version.
In terms of sizing the UL version has width dimensions of approximately 200cm at the shoulder, 170cm at the hips and 150cm at the foot end while the deluxe is 220cm at the shoulder, 205cm at the hips and 187cm at the foot. For an idea of weights a -8C UL double in regular length with zip/drawcord footbox, 15d shell and 10d inner fabrics and 850 fill down is approx. 960g for the quilt itself while a dlx double quilt with the same options is approx. 1130g.
At this stage the UL double is basically ready to go while I'm still in the process of getting templates made for the dlx double.
Some photos of the UL double:
With adjustable top opening extender
Fully opened in blanket mode
Double pad strap system uses non elastic ribbon with adjustable ladder lock buckles to tightly hold your pads together. The double quilts also have the same buckle attachments that mate with clips on the pad straps to help hold the quilt in place as you move around.
Footbox fully closed up
A nice way to use the zip/drawcord footbox when you need some warmth but not maximum warmth is to have the zip undone and the drawcord mostly pulled in (experiment with how much you tighten the drawcord), this causes the end of the quilt to form a cup shape to cover your feet while having extra width compared to when the zipper is open. This also works great for the single quilts.