So Gerry, I've been mulling over your response:
As far as how hot you burn, if the temperature isn't high enough, certain gasses will not combust to give a complete burn and you might as well just be building a regular wood stove that burns much cooler (and often dirtier).
While I understand what you're saying in the first half of the sentence, about the significance of the high temperature, I'm still questioning the second part, is a batch box built with full, uninsulated bricks just as inefficient as a regular wood stove? - my design started with s J-tube, and then evolved into a batch box. the J-tube is already much more efficient than a regular wood stove due to the tall riser and the thermal mass. By converting to a batch box I'm adding the improvements of a secondary air port and increased turbulence. Are these added features non-functional in the absence insulation? While the fire will take longer to heat up, and while that escaped heat may be "robbing" the fire, it is also heating the mass and my house, which is my prime objective (this is the point mason heaters are making to me). As I've mentioned, I'm building this in my living room, and really wanting to avoid regular tear downs and rebuilds, so I'm wary of insulative materials such as CFB that appear to be much shorter lived than fire brick. This trade-off is a fascinating question to me and I'm surprised I don't see it elucidated elsewhere on this forum, or maybe it is and I've missed it.
So I guess I'm still on the fence about whether to use CFB in my design or not, I'm going to consult with a mason heater today and will report back my findings. Meanwhile thanks for helping me puzzle through all this.