Korps,

There is no magic setting each engine is different. Try starting with the needle valve at two turns open that should be on the rich side. Get the engine running and lean it out until it just peaks. Its better to run a bit rich than too lean which most often ends up the engine quitting and a deadstick landing.

Hopefully the low end or idle mixture is properly set so the engine comes up to full power smoothly when the throttle is rapidly advanced. If not that will need to be adjusted as well for good operation.