Nice work. Ta.
Read on BPL I think, to get something like the 'true advertised' thermo value of your bag/quilt your mat must be at least R 4. Recently using my new Cumulus quilt 'rated' to 6 on an Xlite I get this with lightish thermals. Sort of lead me to keep my Xlite rather than go an Xped -even though I wanted to try the Expeds comfort. I bought it under the old regime but as an Xtherm owner as well, it always felt 'warm' to me in comparison. Warmer that is than I might expect at R3.2. Know someone that uses the Xlite with the 2mm reflectix stuff ski touring every winter. Potato chips ahoy!?
Although can't say that anymore- it's pretty quiet.
The Xtherm feels far warmer than the STS equivalent (which has gone down from well over R5 to just R4) which I had and sold.