Since I imagine many have followed this thread, here is the set my gunsmith both uses and recommended to me as I worked on my 1964 Singer 7-33. I included a large photo so you can see the specifications chart on the lid, detailing the blade thickness and shank diameter of each bit. I asked him if this wasn't a bit of "overkill" given the high price. His response was compared to the cost of having a screw custom machined, these are a deal.
Robert