The top termperature
The top termperature required by your kiln for your results will vary from anybody else’s. You need to find the temperature at which your project will achieve the results you want. You will do this by looking at what is happening. The views should be for very short periods to save your eyes.
You can do two things to get flatter results – extend the time at the current temperature, or raise the temperature. The best is to do the heat work you have to do at the lowest practical temperature you can achieve. So to be specific, you can use the same schedule, but raise the temp or use the same temp and extend the soak.
The main element in fusing is the thickness not the diameter. So as you are working with relatively small pieces the same rate of advance should be acceptable. When you get over about 6″ you need to take more care. If you don’t want to figure out another schedule, just use the one for then next thickest.