I can tell you about the Great Catherine Palace.
Tables were laid in the center of the room. long rectangular ones around the perimiter and round ones of ten in the center. the walls were lined with tables, holding extra glassware, plates, etc etc alternating with empty tables for the food. Each two guests had their own server who attended to filling glasses, serving and clearing. Food was plated in the kitchen and carried under covers to the hall.
This was the invention of "Service Russe" where plated food was brought to the diner instead of the diner serving themselves from a platter. It was the only way to possible serve 500-1000 guests in any easy fashion.
Valets would accept wraps/cloaks upon entrance to the palace and they would be returned upon leaving. Im not sure of where the toilet facilities were, but am sure they weren't far. Palace guards would be stationed at key places to keep people out of restricted areas.