One of the best Mods for the Sig Lt-40 is the addition of some tri stock to the fin to give it more strenght. It really helps. I had a very bad crash that Killed my Lt-40. I had not used any tri stock to attach the fin and the crash knocked it iff in such a away as not to damage it. It broke off the plane at the epoxy joint.
I had used 3 min epoxy. In building my new plane I have reinforced the LT-40 in all the areas that it failed and I aded the Tri stock to the fin.