OK I will look up a couple of options for you and post them here as well. The very best thing would be a programable on off control to hold the temp where you want it. I have a pyrometer (nonprogrammable) I can loan you to try. If you like it you can order one for yourself. Just let me know and I will put it in that box I am sending you. You could learn the kiln and make a chart when you need to add heat and shut it down. As it turns out the company that makes this stuff is in Fort Madison IA just 20 minutes from here. I will call them today and see what they recommend.
Most likely the kiln is setup for a cone (a cone melts when it reaches temp and turns the kiln off) You will need a cone as a safety feature anyway. I have a pile of them and you will only need a couple. This cone will only function to turn the kiln on. You do not want to wire it up because that is not safe. Also many kilns have another safety feature built in. There maybe a timer that will shut the kiln down after so many hours. Can you send me a text of the control unit you have.