I don't really know whether I can get any tickets in advance at all but in the event that none are available, I will do what I need to do in order to get into the place as the date comes nearer. Frequently, the ticket situation loosens up a day or two before the performances. I will also inquire about standing room.
I would also expect that there will be tours of the interior available for a fee. This now appears to be SOP everywhere and here, where they actually have something to show, it is a probable.