I did my 3rd fire yesterday and my 4th here today, with the temperature of the oven dome getting to 300 and 400 degrees, respectively.
The 3rd fire started with just one log (with newspaper and kindling) then I added another log or two as it was going.
This shot was taken at night, obviously and you can see the ice on the outside of the oven from our Texas cold snap.
With the 4th fire today, added three logs and really got it going. I moved the fire (embers and remaining burning wood) to the side and the oven floor was over 600 degrees in the center of the oven (under where the fire had been). I'm going to track how much heat is retained by measuring every 15 minutes. Away from the center, the temperature was more like 300F. After 15 minutes, the 600 had dropped to 400. When I get a larger "real" fire going, the oven dome and floor will get much hotter and will retain more heat.