From PZ-IV G model onwards the hull was lenghtened. I do not know to what lenght but 5.92 meters may be the longer hull?
At achtungpanzer
http://www.achtungpanzer.com/pz3.htm
It states: "Ausf F1 was the last of Panzerkampfwagen IVs based on the short version chassis".
My oppinion for icon sizes in general is that it is nice to be able to see the icons well. Sometimes it is good to have some compromises made. Examples of maybe too small icons is the Italian "CV" tankettes and Soviet BA-64 armored cars. They are so small that it is wery hard to see sometimes.