I cannot locate the internal notes we had on the old pump used by the O.S. Max .61 SF/RF pumped engines, but I think it's something like this:

First set the high-speed needle on the carb to exactly one turn out from closed. At full throttle, with the engine running, you adjust the top screw on the pump to get the high-speed mixture leaned to peak. Retard the throttle to idle and adjust the idle mixture. Adjust the lower screw to set the point where fuel returns to the carb. You have to work between the idle RPM, idle mixture, and screw adjustment to get things set where the engine will have a good top end, a good idle, and good transition.