Got a 3 layer Insultex TQ that I have used up to 45 F to 50 F, no problem. Lots of venting.
You write that you are using 1.1 ripstop. Is the ripstop coated?
I use uncoated 1.1 ripstop because I want as much breath-ability as I can get with 3 layers of Insultex and with Insultex, the coating is redundant and superfluous.
Those who sacrifice freedom for safety, have neither.
Do not dig your grave with your teeth. (Unknown)