Do you think the dome has to be flat or could it be curved with 6" at the highest point? Steve and I are trying to go over what would be the best way to start a mod. If it doesnít work, then we will try something else. Do you also think I need two stones for the deck floor, or will spit firebricks be okay? I have two soapstones. Do you think either of them could work somehow as a floor or would firebricks or some other material be better?
Curved, relatively tall domes work fine in WFO scenarios where the ceiling is 1100 F. and there's an active fire on the side radiating energy onto the roof and down towards the pie. Tall ceilings also work in ovens where there's a top heat source like a broiling element or gas burner. A 6" ceiling will work in a high BTU burner setting IF all you want are 5-7 minute NY pies. If you want to trim the bake time, the ceiling has to come down. At least, I'm pretty sure it will.
One of the advantages to cordierite is that, with the ceiling close enough to the hearth, you can preheat both the hearth and ceiling to 750 and, with a good blast of heat coming from below, end up with a Neapolitan sub 2 minute bake time. With firebrick, the pre-heat has to go higher (815ish) and, although that does favor the top heat a bit and should allow you to add a little distance to the ceiling should you need it (4" instead of 3"?), 815ish feels a little harsh for a Weber.
A soapstone hearth will favor bottom browning, so, in your most likely handicapped top heat scenario, it's not a good idea. I'm not really in love with a firebrick hearth, but out the two, it's a much better choice. Soapstone could be viable as a deflector, though. Maybe.