Q and A are constants because I am using my body and the same bag for all tests. The only variables are R and DT. So by measuring DT, I can calculate R.
I used the Thermarest Standard Pad as a comparative reference at R value = 5. This pad was verified as a reference standard by the EN13537 process. For the same environment I measured these values:
a=Thermarest Standard average DT(3.6F)
b=POE Maxlite average DT(5.4F)
a/b*5=R value of tested pad
I think of this thermal test as being similar in concept to your wind shirt test achieved by making a fabric cup and blowing through it. Neither of these tests would pass as International standards, yet they still get the job done. I had to pick nights in which the ground temp and air temp were the same as the reference test.
By contrast, the bottom of the BA Insulated Air Core, fully inflated, increased by 11.7F average.