Added a piece of 1" thick ceramic insulation "blanket" to the inside of the fire door. It fit so well that I did not even have to glue it. So far the results are pretty encouraging. There is a noticeable difference in the amount of heat coming from the door when the stoker is running. Cost for the insulation was $24, and there is enough left to do my brother's EFM as well.
I am only running the EFM for domestic hot water until the drum is empty, then I need to shut it down and clean the fines out. I also have a clean out tee to replace the 90 degree elbow currently on the flue outlet of the boiler.