Van's anwser to my problem was quite short : if you don't have the two rivet diameter edge distance we recommend you order a new angle. But when asked what about the two other pieces that got holes they just said to remove the holed flanges and rivet on new ones made with aluminium sheet. I'm not sure I'll do this as there are two pieces involved on the front spar, so today I'll see what can be salvaged and then place my order. A picture with the complete stab, and the confirmation that I need to order new parts.