Mark,
the quilt is actually not rectangular, it is 46topx34footx76long. It only looks rectangular because of the low angle of the shot from the foot end.
Making a climashield quilt is very easy in comparison to a down quilt. for me i can make 2 climas in a day or 2days per down quilt.
what i do is put the zipper up the sides of the foot end. I am using #3 coil 26" zips from OWFINC.com. i also use a drawcord at the foot to close it up. I have no trade secrets, i just do MYOG, and the new Jason Klass standard, HSEDI (i'm the someone else). The gear i make to sell is the same as the gear i use myself. I keep no secrets about how i make it or what its strengths and weaknesses are. ask and you shall receive.
For a down quilt to 30* i'd suggest 2" loft, you could get by with 1.5" according to some, but i'd use 2" to be safe.
My original site tmoutdoors doesn't offer much info so i am working on a new site (and new name). it has sizing advice and more info enlightenedequipment.webs.com check out the quilt info and e-mail me if you have questions. Eventually when i feel i am happy with the site i will remove the tmoutdoors one and redirect to the new one, but i'm waiting to upgrade my services and get the .com first.
-Tim



