Fascinating thread..a few thoughts from an exile...
If you are going to the trouble and expense to do it professionally, it is not a one off day is it? It needs to be an exhibition that last at least a month but preferably a whole season (2020/2021?). You can choose the hours when you open.
I think it has ideally got to be somewhere at Edgeley Park but surely there must be a lounge in the Cheadle End that can be given to it.
I know suedehead's collection is amazng. But maybe the audience could be broadened by making it an exhibition of County memorabilia with suedehead's collection as the star of the show. There must be people out there with programme collections (I've got a fair few), ticket stubs, photographs, autographs etc?
I think you could add value and attraction if between the various exhibitors there could be some items for sale or raffle. This would also offset the costs of putting it on.