No one has an answer to this question and it has been theorized that with the current technology, it is probably impossible to have the best chess game played.
Chess is partially solved, but the beginning position is the hardest part where to say where the best move lies.
1. Has there ever been 2 teams of Grandmasters playing one game of postal chess with the stipulation that books, computers , going over variations on a seperate board
etc are allowed?
2. Is there a way to tell if each side played perfectly, would it be a draw? Or would the tiny advantage of having the first move snowball into a win?