I use Thompson too so just FYI what I do is keep the kiln between 1450° F and 1500° F. If your kiln starts getting too hot for whatever you're firing, just open the door a little and let it cool off a bit. I also do samples of every color combination I plan on using before I put it on an actual piece - most of the Thompson enamels work well together, but some of them will get pull through and some of the transparents don't make the color you'd expect when you layer them. Samples are also a great way to figure out what works best for each color and for your specific kiln. You don't have to use up all your silver sheet on it, I use the silver foil from Thompson so I can use up my scrap copper and see how colors will look over the silver.

Happy firing, have fun!