OK, you need another kettle
An old black 18 OT will work. I think the sweeps might come in handy. And as I think about it, a 22 will work nice as you could build a round table around the oven, and it allows for a larger oven. Legs can be shortened as needed.
You'll still need the three pots...
The smaller one sits on the charcoal grate. This is the base of the oven where the charcoal goes. Large holes, or the bottom removed since it's sitting on the grate. Block the grate around the (outside) base of the pot. The area under the charcoal grate is now an air chamber.
The next size up sits (inverted with the bottom cut off) on top of it. This is the top of the oven used for the skewers, and slapping on the naan
The largest pot sits inverted in the bowl. This is the outside of the oven, and holds the insulation between it and the smaller pot. The kettle bowl holds the insulation down to the charcoal grate (the area you blocked off).
The only "problem" I see so far is that this is a dedicated setup. A brownie would look nice as it would complement the terra cotta.
Hey
@Shaun you have a brownie bowl, Yes?
As an accessory for a Weber Kettle? An insulated large cone shape that sits on, or below, the cooking grate tabs? Double pots? The pots can get real heavy to move around.
I'm over thinking it. Inverted vortex under the cooking grate. Inverted pot on the cooking grate. Done.
You still need another kettle