I made one of Ray's quilts, though but I modified the design slightly. I agree that it can be very difficult to get the fabric and insulation together through the machine. What I did was simply hand baste the insulation to the shell, then turn the quilt inside out, then topstitch the edges. Even topstitching is not trivial. Handbasting takes an extra couple of hours, but if you're an amateur sewer like me, you probably save that much by not having to seam-rip your mistakes. Seam-ripping with insulation is a real mess, by the way.
Some people talk about use a piece of thin plastic, or even a piece of stiff paper, like an business card, between the presser foot and the insulation to keep the insulation from snagging on the presser foot.
The modification I made to the Ray-Way quilt concerns the so-called gorget. I just extended the quilt an extra few inches (I am 71" tall and made the quilt 92" long), then I sewed together both foot and head ends to make both head and foot pockets. The head pocket is only partly sewed up, so there is an air hole at the top (middle of quilt), which can be place directly over my face when lying on my back, or which will allow some air in when lying on my side. Pulling the quilt over the head and breathing under it increase warmth ENORMOUSLY. I haven't noticed any moisture built-up in the head region. Body heat seems to dry everything out there. In the foot region, I always get dampness, whether with polarguard or down. My feet just don't generate a lot of heat.
My feet also don't seem to be bothered by cold, perhaps because I walk in sandals so much, even in cold weather. So I didn't actually make a full foot or head pocket. That is, I didn't sew the extra 10 inches down the sides like Ray recommends. Instead, I just sewed together the ends. At the head end, the draft stopper prevents drafts, while at the foot end, I like drafts because I hate having hot feet.