Hi Dan
The wire is shot in with a small but powerful water jet ( you need a small start hole )
The water jet acts as a guide for the wire and it keeps it perfectly centered.
The wire goes done with jet while the machine slowly feeds the wire.
On this machine i used 0.25 wire but 0.1 or 0.05 mm wire can also be used.
Don't know exactly what you mean with the second question , make me a simple drawing so i can answer that one.
here is a nice youtube that explains a lot
http://www.youtube.com/watch?v=GDLZBz2uOL0
Eef