You could also try to make a pressurized stove. I have found the efficiency is better with a pressure stove. http://zenstoves.net/BasicPressureBurner.htm
I had that same problem with the double wall.
Or using a pot stand. http://zenstoves.net/PotStands.htm
Or build a side burner stove. http://zenstoves.net/BasicSideBurner.htm
Because remember the smaller the distance between the jets and the pot; the less hot it will burn.
zenstoves.com is probably the best place on the net to learn about any sort of stove you may want to know about.