i just hooked this up over the weekend actually. my quilt was supposed to have grosgrain loops on all the corners, but they forgot. so, i shook the down out of the corners of the burrow, and attached some jrb grip clips. i may just hand stitch some grosgrain on myself. just run some adjustable length shockcord off each corner, and get busy tweaking.
the burrow functions very much like a jacks r better hudson river, this assuming you have the snap footbox obv. its a little hard to get it to fit right as the non-dramatic differential cut makes it easy to smash insulation as you dial it in. cool thing is though, the drawcord in the top and bottom channels does a pretty nice job of sealing gaps.
i have not taken this on a true overnight, but i was warm in the 30's for a few hours - i was using a 20* burrow.
although i probably won't use this a lot... it is cool to be able convert for a friend, so they don't have to use a pad.