Well, I'm sure you're right. I'm only making preliminary plans, not even on paper yet. I have 1-1.5 months before the bricks arrive, so I plan to do quite a bit of research.
Btw, the bricks are 9"x4.5"x2.5". So two bricks for a floor, two bricks for walls, and two bricks for a roof ought to give me a 4.5"x4.5" chamber. Some angle iron or metal bands to clamp it together and I might be able to forgo the cement.