about categories:
AdminCP -> Arcade -> Group Permissions
you can define "Category Permissions" per usergroup there...
about your parallel installation of two arcades: what do you want to do about this ?
One arcade seperated for premium-users ? No need for this, just use category-permissions
You may also restrict some permission for the "normal" players, all done in the usergroup settings: plays per day, posts required to play ect.