have something down to a fine art = have get something down to a fine art :
achieve a high level of skill, facility or accomplishment in some activity through
your finest hour :
the time of your greatest success
1940 - W. S. Churchill - Speech to House of Commons - Let us therefore brace ourselves to that duty and so bear ourselves that, if the British
Commonwealth and its Empire lasts for a thousand years, men will still say, 'This was
their finest hour'.
the police of a specified city – North American informal
2000 - Nelson DeMille - The Lion's Game - As I indicated, I was a homicide detective, one of New York's Finest.