I think he is referring to milling the battery slot. So that you can move the batteries in toward the center more. But that looks like a good idea. I just got my FTTC3 and am getting ready to mill the battery sectiion, looks like I might be milling that section as well.
Looks really good Manfredo!
Does anyone have any pics of the battery modification. I have an idea, but I would like to see a pic of it.