Hi!
Don't be afraid to change the setting of the fuelneedles...they have no specific "best " position......You have to learn how to set them by listening to the way the engine sounds and set them accordingly...! This is very easy when you now how to do it.
Remember to always set the highspeed needle firts then the idle needle.
Before take off always piont the nose of the plane straight up
and adjust the highspeed needle a little rich so that engine rpm drops slighly (300-500rpm). This is easy to hear by just using your ear....a rewcounter is not at all necessary!

Regards!
Jan K
Sweden