Talon (by the way, what is your name, it is strange to call you "Talon"), thank you very much for your reply and the tips. I think I understand what you mean, but to me, it looks like it means recalculating all the cutting angles (especially between the two different parts of FF2-FF3). I will make some simulations with the 3D software first.
... And it is the second time I cut, bend and weld the FF2-FF3 tubes (first try was awful) and I was very happy with the second one
But thanks a lot. It is very helpful.