Dear Alfonso,
I am very sorry to hear about this lost. It is very sad to loose 2 F3A ship.
At list on my model as well as on Rune's model the H.Stab, when the H.stab installed properly, results in having 3mm gap in H.Stab Leading edge
and 1mm gaps on H.stab TE. (You can see it is this message of Rune pictures).

My question is if you had these gaps also and if yes how did you fix it.
TS suggested to push the 2 parts of H.Stab to the Fuselage and then to have the securing screw to hold them tight against the fuselage.
This very wrong suggestion. The only way to handle it is to fill it will plywood or other aviation composite material as having
the screws holding the 2 tabs tight applies un necessary force on the joint carbon pipe

Amram