This is where the misinterpretation begins. Most guys think that because there are
two adjustments on the carb....the low speed, and the high speed....that there are
two avenues of fuel supply. There is only one. The myth is that "if the LS is set too
rich, it will effect the HS throughout the function of the full range of the carb". This
does not happen.

Once the carb goes past the "idle range" there is only one place where the fuel can
come into the carb. In fact, this is the only place where fuel enters the carb, ever.
The fuel comes in through the HS needle....no where else.

Another Internet myth is that there is an "idle circuit" associated with the
LS needle. There is no such thing. In order to have an "idle circuit" there has to
be a separate channel for fuel to enter the venturi of the carb. This of course
does not exist in these type carburetors. This is where most guys go wrong,
thinking that there are two "fuel adjustments", and therefore two places
where fuel comes into the carb.

This is why the Webra manual correctly states:

b. the idle needle (2) only affects the idle range

The fact is....even though it may be hard to accept....the LS needle does
not, and cannot effect anything but the "idle range". Because once the LS
needle is "clear" of the nozzle (spraybar) it can no longer restrict the flow
of fuel....and the important thing to remember is....the only function of the
LS needle is....to restrict the small amount of fuel that is allowed to pass
past the HS needle....when the barrel is near closed, or in the "idle range".

Think about it.

FBD.