I'm assuming these are SU carbs?
Balancing is pretty straight forward with a vac gauge on the carb mouth.
Mixture wise. It's important to check float levels are correct (as this alters the fuel level in the main jet)
That the needle jet in the piston in side the dash pot is correctly seated, the correct size and not worn.
Mixture is then adjusted at idle by using the little "tickle" button to slightly lift the piston and check the idle speed rises and then drops back.
Adjustment is underneath and once you know where it is you can do it "blind"
