You'll be fine!
If you go slow, don't get the fire too hot, or let it run to long, you'll be fine. Gently up and down, up and down. You're seeing how much moisture you have in the oven. Shoot for adding 100F each day, just letting the oven reach the temp you want, then letting it burn out.
Let us know how hot you think your oven is when your metal thermometer explodes.
Are you thinking of getting an infrared?
James