Like others, I'm really looking forward to seeing the results of the 1/2 inch plate.
One of our Tampa pizza eaters, StrayBullet, showed me his soapstone setup last weekend along with a tasty slice. He commented that in a conventional oven, the soapstone takes several hours to reach temperature. I saw the article in a newspaper and shared the idea with him.
There are a lot of bright folks on this form, and contributing to this thread, but the reason I'm so interested in a picture of the underside crust is that I'm not sure what the result will be. Steel is very conductive. One might be able to preheat the oven to 500-550, then turn on the broiler for a few minutes and increase the steel temperature to 600F or 650F before throwing in the pie. As long as the broiler stays on, the top of the pie should cook rather quickly. I'm guessing that the steel won't have to be 800F to cook in 2 minutes.
To me, these test results are hard to predict. At the last Tampa pizza party, we tried to create a VPN pie on my rotisserie grill. A pie made with 00 flour was thrown on my corderite stone at 825F. The result was a scorched crust in only a minute or so. I'm guessing that cordierite, with flame licking the underside, transfers heat better than a wood-fired oven and firebrick base - or I'm just a bad cook. Either way, there goes my certificate.