Sion selling details were the following :
Ticket sales
Tickets will be available to Hospitality Members, Season Ticket Holders, Official Members and Fan Card Holders who attended Rubin Kazan (05.11.15) and have had their travel visa and boarding pass approved by the club.
On sale Monday November 23 from 8.15am GMT. Supporters who purchase during the above sale are guaranteed a ticket.
Tickets will then be available to Hospitality Members, Season Ticket Holders, Official Members and Fan Card Holders based on attendance at the following European away fixtures during previous Seasons:
Bordeaux (17.09.15), Beşiktaş (26.02.15), Ludogorets (26.11.14), Real Madrid (04.11.14), Basel (01.10.14), Zenit (14.02.13), Udinese (06.12.12), Anzhi (08.11.12), and Young Boys (20.09.12),
Attendance at nine games: On sale Tuesday November 24 from 8.15am. Supporters who purchase during the above sale are guaranteed a ticket.
Attendance at eight or more games: On sale Wednesday November 25 from 8.15am.
As the number of qualifying applicants exceeds the number of available tickets, we cannot guarantee that all who apply will be successful in securing a ticket. Those supporters who are not successful are urged not to travel.
If the club use the same system and Maribor is a similar allocation to what Sion was (564), then Spartak will be priority for Maribor then maybe 10 or 11 back to Basel. If Maribor is a higher allocation they may stagger sales.
A lot of the supporters going Moscow would probably qualifiy for Maribor anyway without the credit !