There are two of them:
- click adjustment knob - responsible for idle adjustment and revs up to 1500-1700rpm
- full range adjustment - responsible for adjustment across rev spectrum, also idle
Both are on the pictures here:
https://www.sl113.org/wiki/Fuel/InjectionAs a Full Member you also have access to Linkage Tour, which is describing idle adjustment procedure.
I am also enclosing picture of my FIP with marked screws.
There is also a screw in the throttle, it is tempting, but it is not for mixture adjustment. It is just a stop screw for stopping throttle in certain position as closed (Linkage Tour explains how to do it).