My Italian floor corker lightly scores the Nomacorc 900's I use and I have no leaks. My storage conditions are not ideal, so the temperature varies from 58 F to 72 F. If the bottles were going to leak I'd expect to see it in the summer. [I store bottles on their side.]
If bottles are leaking, I agree that oxidation is a potential problem. OTOH, if the wine is not getting out, I don't foresee O2 getting in more than is normal.
Before I switched to Nomacorcs, I had a problem of mold on the outside of the cork AND about 10% of the bottles exhibited small leaks, more like weeping in the first few weeks or months. I had bottles aged 2 years, that when opened had small amounts of leaked wine inside the capsule, but the wine was fine. IME the likelihood of oxidation appears low -- which doesn't mean we should not address the problem, just that bad results are not as common as may be believed.
After corking keep the bottles upright for 3 days to let pressure normalize, lay a case on its side for a week or 2. If bottles are going to leak, you'll probably see it fairly quickly. If not? Store upright.
BTW -- the 1.5" 900 series is the most common Nomacorcs I've seen on the net. Unless a different series is specified, that's most likely what you get.