I noticed this part and remembered when I started with my 63FZ , The low end needle is a airbleed, the more you screw it in the richer it gets, Backing the screw out will lean up the low end and I too agree to start with the reg flush with the engine. Also it will be hard to get a good setting with less than 20% nitro, YS loves the stuff. When you do get it in the air keep it a little rich for the first 10 or so flights, I started to lean it one klick on the 7th flight and one each flight after that. With the 63FZ one click is plenty. These are sensitive engines when it comes to the needle valves.

Hope this helps
Dauntae