The Nittaku ball IS vastly superior. The QA is two levels better. Not saying that there are no good DHS balls, it’s just that you sometimes get a bad batch. Never had that with Nittaku. Those are always 100% round for me.
https://fc-koeln-tischtennis.de
http://www.rg-porz.de
http://www.djk-spinfactory-koeln.de
All 3 of those clubs have many high lvl players (way higher than 2000 USATT)
Just pick the one that's closest to your location. Maybe call/email them before and announce that you would like to visit.
Just pick any of the new latex based glues. They take a bit longer to dry but you still have to get it right on the first try. Repositioning was only possible with the old glues, not the new contact glues.