wrote on Dec 20^th, 2008 at 2:06pm:

I think if one drills a 3/16" hole in parts he wants to heat check, a candy thermometer would work well.  After awhile though, it wouldn't be necessary because I'm thinking this is a "feel" thing.

 I'm not sure how high a candy thermometer registers?
Since most bake goods call for 400 degrees or so, I went with a small high temp gage, similar to a meat thermometer. Round head with spike tip.  I found mine at of all places, a heating and cooling supply place! Around $10. It registers from 50-550 degrees, so you could bake meat if you desired. You could easily drill hole at top of Freden model or similar oven and insert thermometer. That's what I do on my flashing oven.  Once you see at what temp your getting the desired results, then you'd have your "feel" for where to set the oven.
 You still have the problem of rotating pan for even baking, but I'm thinking once you get your oven, with little ingenuity, you can fix that ;)
  There are numerous plans on the web and on previous posts for making your own oven. I made a conventional one before I made my flashing one and it only took a few hours, with a pair of tin snips, electric drill, pop riveter and some thin wire for hinges. I used aluminum roof flashing I had on hand and just bent the edges over a 1/2" to stiffen the sections. You could also buy aluminum sheets like for storm door repair at the hardware. I used stainless kabob spears for the pan supports.  My oven's whole top swings back to rotate baking pan. My flashing oven solves the rotation problem, because the heat rises up like a chimney and bakes evenly. For the price of the Freden, you can experiment with a few prototypes, save a bundle and get what you really want ;)