Rocket pizza oven and grill

Hi Permies,
I'm new to rocket stuff. I bought some fire bricks, had a play, and now I intend to assemble this rocket oven design.

I cut the bottom off a standard kettle bbq to create a mushroom shaped grilling chamber.
Chimney pot for second half of heat riser.
The side has 3 removable bricks (with gaps by the edges), to form a door.
Pizza stones on the bottom.
1000x600x25mm Vermiculite board to span the ceiling.

The picture should explain better words.
Suggestions please!
Thanks

Hi Marco;  Welcome to the wonderful world of rocket science!

Your picture is not as clear to me as it is to you.
I'm having trouble with dimensions' Just how big is it?

It looks like maybe  you have an open fire at the oblong hole and two exits from your pizza chamber that leadup into the riser?
Is the pizza in a chamber above the fire? Or with the fire?
The "chimney pot" is it clay?   If so I would expect it to crack .
Not sure if you planned on grilling as well as pizza cooking?
Your grill could be a blockage point in free gas flow from the riser.

But playing around with rocket stove's is highly recomended around here!
Let us know with pictures how well it works!

Hello!
The footprint is roughly 600mm x 1000mm.
The lid can be removed for pizza mode, add the lid for smoking/cooking meat on the top (grill mode).
The design is based on a J-tube style rocket stove. Sticks standing vertically in the oblong wood feed.
I think I would try to get the middle up to temperature, then put a pizza inside, probably nearer the heat riser.
Yes, 18" tall terracotta chimney pot from the builder depot. That's the bit that holds me back from revving it too much. I could do bricks all the way up, but I've bought the chimney already.
I'm hoping I can get away with it. So far its survived 2 sessions.
The gap between the top of the chimney and the edge of the top kettle at the final exit point (where the mushroom gills would be) has a cross sectional area similar to the rest of the J-tube path (more so in real life than the screenshot), I hope that prevents a bottle neck.
So far it seems to draw strongly/reliably in the correct direction (in a previous version with smaller general cross-sections), making a satisfying grumbling noise.