My top flight P-47 calls for a similar tank install like the GP extras, I learned the first time I went to put it in, I had no way to install the rubberbands to retain it, so the skid was made out of 1/8" lite ply, and had a 90 degree liteply tab glued to the back edge, that tab sat flush on the back former. It was just a matter of padding out the tank and rubberbanding it all the skid, slide it in and use 2 screws from the wing opening to screw the skid to the rear former, Way easier than fighting and cursing at the rubberbands and the hooks that hold it in, which almost gave me a mental breakdown because I figured that I could build the plane and finish every detail, but I'm not capable of installing a freakin rubberband??!