Original 6 courts are 1-6, 1-3 on one side, wrap around to 4-6, so 1 and 6 are adjacent and 3&4 too. Bottom 6 new courts are 7-12. 7-9 on a side, 10-12 on the other side. 13-18 are the upper set of 6 courts. 13-15 wrap around to 16-18 so 13&18 or 15&16 are adjacent. 13&18 are next to the entrance.

My guess is 9&10 or 15&16 of the new courts will have less traffic, or 1&6 of the old courts.