3/8 vs 5/16 fuel lines

In my 69 Swinger 340 with a 408 w2 I chose to run both electric and mechanical . The electric only gets used for racing or to fill the lines after a long rest . And I used a 1/2" pickup in the tank and feeding into the Holley pump just outside it. My thinking is the pumps will have an easier time sucking up the fuel out of the tank .