cbellero

There are no limits on the sectors you can fly. The limiting factor would be to fly the shortest (by duration) flights from MUC and FRA. It might be a fun, nerdy exercise to determine what that set of flights would be, remembering that some of the shortest flights like MUC-NUE and FRA-NUE are not possible because domestic flights are excluded. I have chosen the shortest flights by distance from MUC and FRA from the route map and then refined the search by looking up the flight times. I might have missed a flight that is listed with a shorter flight time, since distance is only a rough estimator of flight time.

FRA-LUX 175 km 0:40 h + 0:50 h = 90 minutes
FRA-BSL 282 km 0:45 h + 1:00 h = 105 minutes
MUC-PRG 266 km 0:50 h + 0:55 h = 105 minutes --> endpoint for 6 hour pass
MUC-GRZ 312 km 0:50 h + 0:55 h = 105 minutes
FRA-ZRH 286 km 0:50 h + 1:05 h = 115 minutes --> endpoint for 9 hour pass
MUC-TRS 309 km 0:55 h + 1:00 h = 115 minutes -> endpoint for 12 hour pass
MUC-BSL 328 km 0:55 h + 1:00 h = 115 minutes
MUC-ZRH 261 km 1:00 h + 0:55 h = 115 minutes
FRA-BRU 304 km 1:00 h + 1:00 h = 120 minutes
MUC-VCE 320 km 1:00 h + 1:05 h = 125 minutes

That would mean the most segments per person for the different passes would be:
6 hour pass: 6 segments with a remainder of 60 minutes and equating to €41.50/€35.75 per segment on the single/companion pass
9 hour pass: 10 segments with a remainder of 20 minutes and equating to €37.90/€32.95 per segment on the single/companion pass
12 hour pass: 12 segments with a remainder of 85 minutes and equating to €41.58/€36.21 per segment on the single/companion pass

I will let the maximisers improve upon my calculation.