Further to my post elsewhere I think there could be mileage in the following that would free up more room and create considerable more revenue.
It's largely based on the premise that a fair amount of ST holders would prefer not attending games against Celtic but would still appreciate the choice. It's also based on maintaining and not jeopardising Club turnover.
Prices are arbitrary and don't include inflation etc. It's also presumed that we play Celtic twice at home (we'll be in the top six next season anyway)
Season Tickets 13/14 cost £280 (19 home games)
Season Tickets 14/15 to cost £250 (17 home games)
Non ST price for two other games (assumed v Celtic) £25
ST holders price say £20ea game or £30 for two games.
Celtic game treated as a cup game in so much that seats are allocated by the Club and in the designated stand (presumably the main stand)
Tickets made available to ST holders at preferred rate prior to general sale. ST holders can reserve a seat in the designated stand should they so wish.
There could be concern with the status quo re season ticket value due to rearranged fixtures as it is. The additional hassle of Celtic matches could be the straw that breaks the camel's back and have current ST holders seiously questioning the value in renewing. Above could help redress that concern to some degree at least.