Base starting point for the low speed needle is to have the screw head for the needle flush with the outside of the throttle valve of the carburetor. The high speed needle is usually 3-5 turns out from lightly seated.

Cutting out when you jab the throttle to side open from idle means your idle needle is too lean. If you open the throttle to WOT and it revs up some and cuts out, the high speed is too lean. Always set the high speed needle first - start rich and work leaner until you get no better top speed, then back off rich about 1/8 turn. Set your idle needle so it throttles up nice and cleanly after idling for about 15 seconds. It's good practice to do a nice long WOT pass between each adjustment so you can listen to the sound the engine makes. The sound of the engine will tell you what adjustments the engine needs though it takes some time to "get the ear" for it.