Not sure if its already been said but my suggestion would be, every fan pays £100 up front and fills in a form stating the max they will pay, £100, £150, £200, £250 or £300. If we sell 7000 they all pay £100 if we only sell 6000 then maybe 5000 of them are willing to pay £150 then them 5000 get them at £150 and the other 1000 asked if they would like to pay the extra £50 or have their £100 returned. If we sell 4000 and 3000 are willing to pay £250 then we sell them at £250 to the 3000.
As far as cup game tickets go then anybody who has had a season ticket this year get priority then they go on open sale to the new season ticket holders.