Either way you choose to heat the tin, you will have to have a way to keep the tin raised off of the flame. If the fire is too close to the tin (touching it at all), it will burn the bottom of the bread and leave a nasty char on the inside of your tin. I took a wire hanger (non painted or covered in plastic), and bent it into a shape that I found works quite well. You want it to be wide enough to accommodate the tin and flat enough that it wont slide off when you open it. See the pictures below of my stand (which was actually made for my penny stove), and use it as an example.