I worried this to death when I made my underquilt.
I finally decided that "Imitation of excellence" was the way to go.
So, I poured over all the JRB quilts pictures I could find.
By adding velcro tabs that fastens around the hammock tieouts, I have no problem with my diagonal lie with the rectangular quilt.
It's much more important to allow for the curvature of the quilt under the hammock to prevent "squashing" (tech term!!!) of the insulation under you. I made the inner channel 6 in. and the outer 7 1/2 in.
Also: few mention the direction of the baffles. JRB run theirs side to side, rather than lengthwise. Hence, so did I. Most DIY's seem to run them lengthwise.
Re. suspension: I finally ended up with shock cord suspension adjusted tight enough to hold the quilt snugly against the hammock. This finally got rid of the cold spots. Apparently, the curvature designs mentioned above takes care of "squishing"
Last edited by Grinder; 09-29-2012 at 07:15..