Regarding cardboard sleeves scratching your CDs, I've got several CD singles that are in this format. Judging by them, I think you're going to get a modest amount of wear as the CDs go in and out. But most of it is going to be on the edges of the CD, so if you're not recording a full 80 minute disc then it's probably not a problem. Even then, I don't think a very mild amount of wear on the edges is going to cause you too much trouble. If necessary, line the cardboard sleeves with something like that plastic CD soft case material and you should have much less trouble.
After all, I remember all of my 12" records having a plastic or fine paper insert into which the record slid before the whole was inserted in the outer cardboard cover.
Have fun,
Paul
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