I've always just stitched holes closed with matching thread. The mend can be visible up close, but doesn't show out on the ice at all. If you decide to use the beige boot covers, I'd put them underneath the tights. When our synchro team used black over-the-boot tights one year, we just popped pieces of black tape onto the boots where the holes would hit. Out on the ice, you couldn't tell at all. Remember, these are costumes meant to be seen at a distance, so you can get away with things you wouldn't do with street clothes.