neat idea! personally i'd cut some plastic covers for each hole so the tape has some backing, your could make a template by placeing a sheet of paper over the hole and press in against the edges of the hole so they make a fold in the paper (like you might have done as a kid with a pencil and a coin). you may and up with a few different templates depending on the different hole shapes.
what you might also considder if you care about looks is have custom vinyl stickers made
in a big O or C shape (to account for the curve) that cover the whole rim .
we've had some precut white promo window stickers made for out youth house and they wheren't all that expensive... so provided you can get a good price this could be worthwile (especially if you compare the cost & effectiveness with real moondiscs... if you make a few spare ones any damaged ones can be replaced) and perhaps for a little extra cash you could have something printed on them... i'm thinking: a spiral (spread ecomodding trough hypno techniques), logo's (spread ecomodding trough advertiseing), or fake spokes (deny your true nature)
