The proper way to tune weber carbs to a motor is to put the car on a dyno with an exhaust
gas meter and swap out sets of small brass bits until the car produces max power at all RPMs
and throttle positions.

Expect this to take a week of solid dyno time if you are at a shop that has a complete set
of brass bits and people who know what they're doing.

In other words -- webers are expensive and tuning them adds dramatically to the cost. Most
people don't tune them correctly and get terrible mileage and inconsistent performance.
chris