Hi there , Thank for your complete answer, I didn't understand everything but it seems that you think I do not have the correct sizes for holes pads. But I do have the right sizes.
The problem was that with a width set at more than 0 you have the pad size + the thickness of the line so when you use a 0 set-up you have just the right size.
I'm really not familiar with the solution you gave me and tried to have a look on it. I think I'll have to really get through it to understand how your method work ^^
I think I had the right result with inkscape and the tutorial I followed ( in french but i can give it to you if you're interested)
Coming back to you if it not fits to what I want because I need to make a command at the end of the week.
Amaury.