I find that the atlantis drip tip fits fine for me in my nautilus tanks. In fact, I ordered a bunch of atlantis tips from aspire because I love them so much better for the nautilus and mini.
Problem with aspire is that their tips and bore holes on their tanks for the tips are not really a 510. I don;t know what they are so I call them "Aspire Fit" lol. However, those black delrin 510 tips actually do fit in the nautilus and atlantis (but who wants those anymore, right???).
As for the kanger tips fitting loose in Aspire tanks, that's no surprise because Kanger tips seem to fit loose and wobbly on Kanger tanks as well. This is one of my biggest pet peeves about kanger tanks. But they will fit looser in Aspire tanks because Aspire bores are larger than 510.