Got my P3A for Christmas (knew it was coming, but had to wait) and have been looking at some of the 3D printed offerings on shapeways that are SAR related (my wife and I are amateur storm chasers and I want to be prepared). I've seen several different pieces I'd like to get that attach to the gear but they are all sized for the P4. I'm wondering what the dimension difference is between the 3 and 4 for the gear length (front to back) and width.