I have one of these, it's a great plane.
The "balsa on the tail" you've been hearing about is simply a reinforcement to the tail group to make it sturdier.

What you do is;
-Remove a narrow strip of covering on the base of the tailgroup, In the "corner" where the fin and horizontal stab meet. (Not the rudder and elevator)
-Glue in triangle stock on both sides of the fin. (Balsa triangle stock/material can be bought at your hobbyshop)
-Recover with white Ultracote or Monocote.
-Now you got a "filling" at the base of the fin, keeping it more rigid and supported to take more abuse.


I'm at work, but I'll snap a picture of my LT40 when I get home to show you exactly how the reinforcement looks like.