I do not think that two of the same dryers will have the same settings unless they are in the same room and have all other setting set the same way (like panel heights from the belt, temperature, height of the opening, room humidity, room temperature, fan speeds (If there are fans)) Also, every shirt (Black, White, Red, Blue) will need different setting even if the shirts are the same weight.
So in short, if I have the same dryer as you, and I have my speed at 3, that does not mean that you will need to have it at 3 to get the same result.
You have to try different settings, record them in the little notebook and have them for all different shirts you use and all different colors.