The tail dropping slightly when the tank is empty is normal for the ARF. I too thought I had a problem and our head instructor wanted verification that the plane was balanced before I flew it. I bought a Great Planes CG machine and proved to everyone the CG point was correct. My ARF will float forever with a little head wind but as you say if I let go of the sticks on the final approach it will drop more than my old trainer. There are times when I forget to slow down the throttle on the down leg and end up having to do a go-around but usually the plane will land easily within the 200' feet you specified.

Keep at it.