There are patterns driven by holes made with the hole-wizard that you could use. I don't use the toolbox much but I'm pretty sure there is something similar that can be set-up so that the toolbox detects the holes and places the fasterners accordingly to the size of the hole.
i have done this but i cannot share the code.
my addin can insert hundreds of components in a model quickly.
the point of my reply is that you can do it. it is complex but it can be done.
start writing and i can help you as you go along.