SIDAV :
1. There is no bar for the wing. Once the 2 halves are glued (epoxy ) togeather inside the wing joiner it will be super strong. Suggestion : make sure you SCORE all parts to be glued, it gives a better grip for the glue.

2. The rubber gromet on the front of the tank is supposed to fit tight enough that you don't need a support, I still do something like the foam or what ever. I use Styrofoam blocks in some cases, it's light and easy to work with.

3. I don't really understand what you mean by the plane moving left and right without the tail wheel moving ????
RE READ your instructions and REALLY look at the pictures. Your tail wheel steering is controled by linkage off your rudder servo. see pictures # 56, 57 and 60 . Make sure when you pin the tail wheel that you don't squeese the tail wheel mount to tight. ENJOY !!! RED