OBTW - once you get the slow speed needle adjusted you will have to go back and readjust the high speed needle. Also, the throttle trim / throttle stops in the radio will need to tweaked as the idle will probably be higher than is was before.

Another point - after you think that you have it nailed remove the juice to the igniter at idle and see what happens. I happen to use a Hobbico panel on my field box. It has an adjustable glow plug igniter with a dial on the panel which allows me to vary the juice to the glow plug and entirely turn off the juice without removing it from a running engine. If your low speed adjustment is spot on you should be able to remove the igniter (turn off the juice) and let it idle for 30 or more seconds without loosing any rpm. Yes, it may load up a bit and need some full throttle exercise to clean it out but there will not be any noticeable drop in rpm. If there is a drop in rpm because the excess fuel is cooling the glow plug - adjust the slow speed needle 1/8 turn in (lean it out)and test again.

Ya can't do this on your work bench. Go to the field, mount the wing (planes aren't built to take engine torque without the wing mounted - please don't ask), fill the tank, and start playing with the jets. If you have a buddy with a tach - just some additional information to help tune that engine. Just watch out for that prop!

Once you have it running correctly, kill the engine, gently screw in the high speed needle until it hits the seat - counting the exact number of turns and fractions of a turn - write it down - then back it off that many turns. Gently screw in the low speed needle until it hits the seat - count the turns, record it and then back it out. Now you have a record no matter how many times that you bump or accidentally adjust the needle settings.

Em - electrics sound sooooooo much easier and much less messy ...

Good luck.