Nope. Just kidding: 50% of the traffic from 50% of the german GA airfields goes to the "Ostfriesische Inseln". And the typical fuel hub is Papenburg Leer (EDWF). My fuel hub to UK is Lydd. My fuel hub to the south is "Hohenems" / Austria. My fuel hub from the west of Germany to the east of Czech republic (about 80% of my LR distance) used to be Lethnany, now it is Hof/Plauen. It is a fuel price question, and it is now based on experience, not on straight forward available information.

I'm always considering enroute fuel prices. Done a cuple of fuel stops at Luxembourg without ever seeing the GAT from the inside! I've also refueld at Beograd on the way to Greece. And I'm regularly flying to EDMB for fueling, since AVGAS there is typically 50-60€ct cheaper than at my base. At 200L that's a free 100€ hamburger. Yes, no kidding.