Weird ? about small block pulleys

Looking at that chart for the aftermarket pulleys, it looks like higher water flow is 6 1/2 crank and 5 1/4 water pump pulleys. They say for better water flow in slow or stopped traffic use. The 1:1 ratio (6.5 to 6.5) pulleys is for a little more performance. So I'm thinking because my car is more for street cruising I should go with the smaller water pump pulley.