I would like to have a warmer TC floor... any ideas?

Sleepy,

For this old engineer, simple is always better. I wear Acorn Slipper Socks from October through March. The foam between the wool sock and the thin leather sole keeps my feet warm all winter. I had a pair that was wool with fleece lining an rubber soles. I wore those outside and for driving long distances.

Just thinking out loud,

Bill