Jetting is as important as it ever was but keeping the same level of fuel available to it for the duration is often the weak link.
You can actually make minor changes in the tune-up by raising or lowering the fuel level to fine tune between jet ranges but it never has to be that precise.
Early Offy alky motors actually routinely used a "floatless Carb" that had an adequate supply inlet with no needle restriction and an overflow return to maintain the desired level.
As you increase the size of the seat in a needle and float setup, you also need more float energy to control it or you must decrease the supply pressure.
With more float size you reduce the space for the fuel.
Bad news !
The S+S is unique in that you can get it supplied with an adjustable secondary inlet that puts fuel straight into the bowl at whatever throttle position you select.
The adjustment still uses the float circuit also and the overflow canister should have just a small amount in it to verify it was always full.
A simular system can be built for any carb with a float, but it is not often used.
