My feet have never been colder than when in synthetic rubber boots standing in a goose blind 30 some years ago. Cheating can get you killed. I have never felt at risk from equipment using the old ways. They may be the best answer anyone ever devised. The former is the easier to deal with.
Feet are the same.
If you are in an area where it is always frozen wear most of your layering under a light inner moc which slides into a blanket boot and then into a heavy outer moc which always stays outside so its frozen. For places like the great state of Misery you need a fairly heavy leather moc with fabric layers within. The number of layers depends on how sensitive your feet are. If the moc leather is too thin it will stretch so much it may cause a tripping hazard. Greasing the leather helps.