Interesting information from you Belgique..
One cannot help thinking that maybe a tailfin shouldn't just be attached as shown at the image you supplied above..
One would rather suggest a more substantial and solid attachment via some sort of heavy metal beam coming from within the body of the fuselage - like the wings are attached - and then going all the way up to the top of the fin along the front edge - do you get the picture..
I'm not an engineer, but the attachment points, I've seen from the photos and the sketch, seems very fragile to support such a crucial stabilizing part of the aircraft..?!