Good Morning.
On having a re-think, I have come to two conclusions:
a. You are confusing lighting the object with highlighting it
b. If you are doing this on a regular basis, you really need a jig not just for the object, but for the whole set up. Like a scientific experiment you need replicate the thing time after time!
Dealing with the second point first, I would get a sheet of ply/blockboard and mark/bolt the exact position of your jig upon it. Then get two spotlights of the flexi variety (I managed to buy two extremely cheaply in a colour that nobody else wanted for about $10!) Fit blue bulbs to them if colour cast is a problem. As an aside though my digital has a means of setting "true white" with artificial illumination, I find it a fiddle to do this each time I want to take a photo!
Find a position that illuminates your coins evenly without causing undue reflections. Bolt them to the board. This may involve a tent, or if you don't want to do this, a diffuser of some type in front of the bulbs - leave a gap for ventilation!
Paint the jig background black. That will help get the auto exposure right as these auto only digitals are easily confused by white - as I have found to my cost (I must really buy a digital reflex to get the control I want, but they are still far, far too expensive!)
I agree with you about getting up close - I normally stand back and use a f2 85mm on my FE2 as the ideal combination as I can then control depth of field and confine focus to an exact plane. My digital is a lot less controllable and decides what aperture it needs!
I would then set up one or two "catchlights" to give the desired reflections in the exact places (illuminating the Hologram?) you require. If you are using flash, hand held (I am guessing here) that this is what you are doing, you will never be consistent. I think you can now get some ornamental pencil beam type lights that will do - alternatively, one of those small focussing torches.
I think that's my final say (thank goodness says all the very bored onlookers!) and I hope some of my suggestions might have been a help