I am using a controller similar to that one, but it has a 24VDC output to controll your contactor. It's a Watlow series 93 controller.
http://cgi.ebay.com/WATLOW-93-MICROP...QQcmdZViewItem
Works very good. The controller even has a learn function which will learn the heat/cool characteristics of your oven, and pulse the electricity on/off/on in progression as it gets closer to temp. I have 7500W IR in a 12CuFt oven and it rarely overshoots
