I am about to do the 11.5 gal install in the left wing which is still in the restoration stage. The documentation is pretty clear but I have a couple of questions I need help or clarification…Before covering the wing and tank do you put anything between the tank and the fabric? When you are shimming the tank is the objective to get the tank to follow the rib curvature or just be clear of the fabric top and bottom. What do you do around the filler neck? I assume you would reinforce around the neck somehow and seal around the neck with the fabric. Just trying to get this laid out straight in my head before I jump into this project. Thanks