I went to the low 20's w/ a 1/4" layer of CCF 40" wide x 60" long (evazote) & a thermarest prolite 4. I did add a couple 10" wide strips on the sides to boost my shoulder protection to a total 1/2" thick.
Since that trip though I have purchased the Speer 4x4 SPE which should make it easier for me to keep the various pads in the proper place. I also hope that the SPE will allow me to customize the amount and placement of my pads to match the expected weather of the trip. If its going to be warmer I may only bring the Thermarest and the 1/2" CCF "wings" for the SPE whereas if its going to be cold (20* - 30*) then I'll bring extra CCF. I'm using the SPE for the first time in 2 weeks so I'll share how that works then. I also got a 2x2 SPE for my son's HH Scout because it doesn't have a pad pocket & I think the SPE will make it easier to keep him on the pads and warm.
It will .... and it seems to make it easier to shift around with the wings at the shoulders. I agree about using one ccf pad and the SPE ... it helps a wee bit on the condensation ... depending on conditions and how warm/cool you are sleeping due to dress in the hammock.