What are your cold weather mattress combos?

I have a choice:

1. 3/4 length Thermarest "regular" thickness
PLUS full length RidgeRest beneath

2. 3/4 length Thermarest regular
PLUS full length Thermarest Lite (1st light version they made in the '80s) underneath

#1 has been the warmest for me but not by much and
the Light Theremarest packs down MUCH smaller that the RidgeRest, which is nice with all the other bulky gear for winter

I will not be using my Neo-Air in temps I know will be below freezing B/C I don't want any ice that may form inside from my breath condensation to damage the mattress when I roll it up.

Eric