Apparently there are only a few of us that have a sense of humor LOL Dole....bananas
(quote Slusser); You size a venturi based on gpm, you don't size a pump based on a venturi, you size the pump and the plumbing based on the TDH (total dynamic head), pressure required/desired and the max gpm of the peak demand flow rate required for the building.
BTW, a venturi works by increasing the velocity of the fluid going through it, which in the venturi decreases pressure of the fluid flowing through it. That causes a vacuum if you add a hole to the outside of the venturi in the right position and the vacuum can draw in a fluid or a gas, in this case air. And a venturi can be added to any water line anywhere you want to add one.
This is correct in every way. However, I have seen many cases where improperly sized venturi's were installed because the installer incorrectly "guessed" the size of the pump.