Little more info here…
When I refresh a carb it’s almost always just pumper gasket (the kevlar / mesh one) and diaphragm, it’s quick, easy insurance that it’s going to run well and like $8 worth of parts. I call this a “minor” refresh.
While It’s apart I will inspect the fulcrum arm to make sure there’s no visible signs for wear and I’ll check the needle from time to time to make sure where it contacts the seat doesn’t look too worn.
It’s only about 1-2 times per year that I actually replace the needle, seat, fulcrum arm and or spring in the carb kit.
The fulcrum arm height is literally adjusted by bending the thing (gently), generally with a screw driver, to get the top of the arm to sit where you want it to in relation to the body of the carb.
The pop-off pressure is determined by the spring under the fulcrum arm. To adjust pop-off pressure you either compress the spring or stretch it out a little bit to get where you want it. Maybe in an extreme case you might need to cut a coil out of the spring.
If you measure all these variables when you get a carb that’s been “blueprinted” you should be able to duplicate that original work time after time when you rebuild it on your own from there and even then it’s only on what I’d call a “Major” rebuild vs. just the minor ones that I do most of the time.