DON'T get any of those 3! They are the wrong tool. They are only graduated to .0005". A .0005 DBG is almost a guessing tool, you might as well use a snap gage.
Look around, and you can find a nice DBG graduated to .0001 for an affordable price. You have to seach, but they are available. A .0001 guage is SO much more user friendly. Once you get one and use it, you will be very glad that you did. Good luck!