It seems to me there might have been more than one size. I might still have one but if you are in the States the shipping might be worth more than your bits are (if I can find it and have it). I also still have a few and haven't used any of them in years. I see them go for sale on ebay along with HSS Vermont Americans and old Bosch bits. Often no one bids on them.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.