Since I want to get the most heat out of the oven and as fast as it is possibly able to I tested the most important configurations with a 12 inch cordierite stone from bottomlevel to top, going from broiled to conventional while each time letting the oven almost completely cool down. The testing took me 3 different sessions during 2 days but now I know, the IR thermometergun never lies, it revealed the hotspots and the temperature difference from the center of the stone to the edges in all the different corners and to what effect on every different ovenlevel.
The results are surprising and revealing and so much so I thought it was worth sharing, it shows once again how important facts are versus subjectivity as nothing beats measuring and weighing.
The oven was set to 300 C / 572 F during each session.
I started out using the conventional setting (top and down elements together) while placing the stone on the bottomlevel. It took the oven an hour to reach a mere 255 C / 491 F.
After the cooldown I only changed the setting to the broiler while all else being equal. Within 15 minutes the top of the stone was heated to 270 C / 518 F but it was still about that temperature after 30 minutes.
The next day I placed the stone on the second level from the top and again only used the broiler and thats when the magic happened.
Within 1 minute the center of the stone reached 80 C / 176 F
Within 3 minutes the center of the stone reached 160 C / 320 F
Within 12 minutes the center of the stone reached 277 C / 530.6 F
Within 14 minutes the center of the stone reached 297 C / 566.6 F and which was around the same after 30 minutes.
I would have never expected such a result as I would usually use conventional to heat up the stone which always takes about an hour or so before the thermostat light switches of. So for a few years I pretty much wasted a lot of energy while not getting the most out of it...