You could super-glue the rounds to the dislay surface, whether sideways or upright. If drilling, you can use a hand drill; they still make them. Wrap the round in rubber, like an inner tube, clamp it carefully in a vice, drill by hand (non-electric). There are two types of hand drills I am familar with. One is a push drill (a cylindrical object that revolves around a central axis as you push downward). I don't recommend this one, as the pushing will tend to dislodge the round from the vice. The other is a rotary-handled gear-driven crank drill. It looks sort of like an egg beater with a drill bit. That should do the job with a bit of care. Make sure both ends of the round are aimed in safe directions, and wear eye protection. Hearing protection would be useful, in the event the round goes off. Good luck.