Try the chemical warmer insole, not just the toe warmer, but the whole insole. I have not had cold feet since I started using them on every hunt. I hunt Dec. in Minesota so it can get pretty cold.
I think a combination of a good boot, the boot blanket and a chemical heater in your boot, you could withstand any temp.
I know I saw a Realtree where David Blanton was hunting in Saskatchewan and he was talking about cold feet. He said the only thing that worked for him was to wear good socks, and them once he got to his stand, take his boot off and put on the boot blanket and then put in a chemical warmer pack.