You run the smallest carb that will support the highest average RPMs the application is likely to see. You want velocity through the carb for efficiency. Some manufacturers tried variable venturies to do this, but they didn't work out well.
The 4 barrel carbs with vacuum secondaries are designed with this in mind. Small primaries where you run 99% of the time, but still can pull 5500 rpms+ when the desire hits you.
If you pull up the performance stats on all the 258s over the years, the one with the most balls at the bottom end ran a small, 1 barrel carb. It was in a J10, IIRC, and had significantly more torque than the 2 barrel variants. The max torque was all available below 2,000 rpms, right where you want it for heavy pulling or off road running.
eta: the 258 is a stroked 232
418 miles on 19 gallons of gas. Can't beat the BBD !