1. I did not add anything to the tail. I built it as per the plans. Some add triangle stock to the tail after assembly for added strength.
2. CA hinges work great. No need to change.
3. Balance the plane after it is completely finished with everything installed. (fuel tank empty)
Balance at the spars for CG and then balance laterally by holding the plane up by the nose and tail.
4. I used the supplied decals for the windshield.

Hope this helps.

These are my opinions and others will have their own. I built the plane as the directions specified. The plane is solid and flies well.