Here’s the standard venturi selection chart for MAX horsepower. If you set up to this chart you’ll end up with

driveability.
Street driveability is 4-6mm smaller than this chart would suggest.
Click to view attachmentAlso going to give you this chart out of the Weber tuning guide (page 21)
Click to view attachmentEdit: clarifying the chart above - this chart from the Weber tuning guide is for total engine displacement. The point being that a vehicle like early BMWs from the 70’s often ran on 30-32 mm progressive carbs with small bore Venturis.
Here is the Weber tuning guide chart for single cylinder per barrel Venturi selection chart - basically the same as the Excel chart posted at the top, the main difference is the chart from the Weber manual has 6000 rpm as the lowest curve while the 5500 curve in the Excel chart is more appropriate to our 914’s.
Click to view attachment