The difference between .060 and .070 inches is more the 10% so it is easily seen. If this were mine I would pull the firing pin and chamber ALL the .070 samples and check for ease of closing, any binding while closing the bolt will be a problem. Ideally you should feel a little fore and aft play in the bolt when closed. Any cases will have a tolerance on the rim thickness probably plus or minus .002 inches (you probably will not be able to see this).  You do not want to order a bunch of cases and find the bolt does not close or closes with a resistance on a big percentage of the cases when you make a volume purchase.