I think your setup looks pretty good. About the two battery packs: is one for the RX and one for the ignition? If so, it would be better to separate them a few inches. The fuel overflow looks fine. I can't tell if the plumbing is correct or not from the pictures. Usually the overflow line goes toward the back of the tank, then out the front/bottom of the plane. The reason to use this extra tubing and have it go "backwards, then forwards" is to not lose any fuel when the plane is pointed down.