My feet are the same too, you can get ultrasound on your feet to guage blood circulation, I haven't but its something to consider because maybe it isn't poor circulation after all.
I use felt paks, with toe warmers or the whole foot warmer or both, then over top I put over booties that I've made with hand warmers inside of those too. I'm good to about -30C like that.
The trick is get the chemical warmers into your boot before you get cold as they really do take at least half an hour to begin to really work.