Interesting, I would have thought CNC would actually be cheaper then doing it by hand, especially that you pay for by the hour?
Careful with the size of the HG, it has to be precise, otherwise you may risk det and will severely limit your power.
I've got a 9180 with a 60mm wastegate. The head is where all the power is made, so its best to do the homework on it. It is rocket science once you start getting into the intricacies involved such as air speed and pressure at different points in the chamber(None of that which I understand tho )