I have set a new personal record for the coldest temps I have been and comfortable in a hammock.. 0 degrees and i was nice and toastie.

Set up on bottom
BBWB double layer 1.1
Mac IX huge under quilt double layer
3/8 foam pad
one super small therma rest
silver blanket

Set Up on top
one old -5 bag with a 40 bag over it
Tyvek cover over the bug netting.

Not a light weight set up but is there one for that temp?? Lots of fun camping when no one else is out..