Thanks Juan & Marc,
I went a little forward: besides cleaning all the remaining pieces off the sprue (hard and boring work because the flashes were many, made of thick and hard plastic) I pierced the tail planes, rimmed them with photoetches from the nice fret supplied by the kit, then I drilled holes in the elevators and inserted control horns made from scratch.
Here the pictures:

tail planes + elevators top side

tail planes + elevators reverse side

detail view of the control horns
Next step will be scratch build the rudder.
Ciao and thanks for watching
Antonio