Another test used to determine if the HS needle is a bit rich is to hold the plane vertical with the throttle wide open - a bit less fuel flows up hill. If the rpm increases then the engine is a bit rich - a good thing. If not, add 1/8 turn to richen the HS needle. Yea, yea - some engines pressurize the fuel tank and this isn't a viable test but if you were using one of these you wouldn't have posted the question.

Once the HS needle is set work on the low speed (LS) needle to obtain a nice smooth idle without any glow plug ignition attached (20 - 30 seconds). After messin' with the LS needle go back and ensure that the HS needle is on.

Once you get it right - QUIT MESSIN' WITH IT.

BTW - lnewqban is a superb source for just a whole lot of stuff - big thumbs up!!!