Hi Ceramic Arts Community. I have an opportunity to custom build a kiln, made by a start up company that, to date, has only made very small (20cmx20cmx25cm interior) kilns. The company is a one man operation. That said, he has been working as a kiln repair technician for many years and is the brother of a good friend of mine. I have concerns about the specifications of the kiln and figured maybe this community might have some advice: Interior dimension 40cm x 40cm x 40cm and exterior 65 cmx 65cm x 65cm. So that gives a wall thickness of only 12.5cm (just under 5"). The target temperatur