I would say 45 degrees rather than 40. But I should add that the Insultex was not compressed by my weight in either the hammock body or the UQ. My earlier version of Insultex hammock used two layers beneath but they were not as effective in holding warmth because of the compression along the weighted areas of the back.
Also, my width of 32 1/2" was a bit skimpy when side sleeping with knees pulled up, which caused my back to press along the side of the hammock. The width seemed fine the rest of the time though.
"Better living through Hammockry"