I've read that a flagpole 40' tall can have a 6'x10' flag on it. Does this mean you have to fly that size or can smaller sizes be flown? We are flying the U.S. flag on top(a 4'x6' or 3'x5')the state flag second(3'x5') the county flag third(3'x5'). Now they are wanting to fly a POW/MIA flag(3'x5'). This will change the order(U.S,POW/MIA,State,County) but what size flags should we be flying?