1. That is where it goes, don't worry, Ballance it with an empty tank, the full tank won't affect CG that much and the affect is positive.

2. Both. You want to wrap both in foam to protect them.

3. What ever you want, just don't cut it. I put a piece of clear tube like bike spedo cable outside or nyrod inside the fuse for it to go through and come out the tail, or you can put it through a hole in the fuse and tape or use a rubberband to mount it at the tail.

4. Get help from someone at the local field so they can teach you the propper method and save damage to the engine plane or you. It isn't hard, but if you get help, you won't be tempted to try to fly it yourself. If you try to fly it yourself, you will crash it.