I built the pizza oven recently and have been working on perfecting my technique. First of all, thanks for the ridiculously simple, inexpensive idea for a backyard pizza oven! I had a bunch of paver bricks laying around so that didn't cost me anything. The two 2' square pavers and the crushed stone for the base cost me around $25.
It took three tries to get the fire/temperature/cooking time figured out. I start with a small fire at least two hours before cooking time. I build up the fire so the whole firebox and oven deck come up to temp slowly. I'm looking for a 4 - 5 inch bed of coals. To maintain temperature, I add small pieces of wood throughout the cooking process - usually 7 - 10 pizzas. (go big or go home). We host pizza parties. We furnish the dough and some basic ingredients and our guests bring anything special they want on their pizzas. Everyone builds their own custom pizza and shares with the others. It's very popular and we can't wait until we can go back to larger groups.
Once I get to about an hour before cooking time, I put a rectangular pizza stone in the cooking deck. It's a little cleaner that way because the cooking deck can get sooty depending on the wood you're burning. At around 650 degrees I throw a little corn meal on the pizza stone and start the first pizza. At that temp it takes around 8 minute to cook BUT, you need to rotate every 3 minutes or so to keep from over cooking the back of the pizza where the oven is the hottest. I try not to let the temp fall below 550. That 550 to 650 range seems to work for me. Good luck with your pizza operation!
