Yes they certainly do "influence" partial throttle settings.

But consider this...."If" you have the carb adjusted properly, top and bottom, the engine
will run crisp and clean from idle to full blast. This is because the carefully manufactured tapered
needle see to that chore. Sure, if the top end is set too rich, it will throw off the whole range.

If the low speed is set too rich, the engine will "load up" and will be running too rich as you
advance the throttle to a point where it will clear out....providing the high speed is set correctly.
If the high speed is set too rich as well, the engine will be sloppy everywhere.

The key is the taper on the needle takes care or everything between idle and full speed, and will
do a really good job of it....as long as the low and high speed are set correctly, the needle takes
care of the rest. Trust me, that's how it works.

FBD.