Good points, especially on the disruption of the UQ seal by the pad........ and YMMV on what gets cold enough to interfere with comfort.
So, before the OP goes off on a quest for a pad that doesn't satisfy and even leads him to be frustrated with his UQ, what do you suggest? To my multiple layers of socks, I suspect Thinsulate leg warmers might be sufficient complement to an partial UQ.
- No more insulation than needed, and
- engineered to take mild pressure without compressing so much the insulation is compromised.
eg: the trimmed sleeves from an old winter jacket or coat.