Well, it can be tricky, but if your idle gap is correct and it's still too many RPM's, your LSN is probably a little too lean.. Try richening it up a little at a time and see how she does! I like to use the "pinch" test to tell me if the LSN is in the ballpark.. If you pinch the fuel line that enters the carb, your motor should rev slightly and shut off within 2-3 seconds.. If it's doesnt rev at all before dieing, the LSN is lean.. If it takes longer than 2 or 3 seconds to shut off, and or revs excessively, the LSN is too rich.. That's just one way to do it, but I've had a fair amount of success tuningthe LSNthat way, although Im having a heck of a time finetuning my SH .28, but that's another story.. Good luck and welcome to the forum!

EDIT:After looking at your post again, I want to make sure you know which needle is the HSN and which is the LSN..(The manual that comes with some of the redcat nitro's has them reversed on their diagram.) So, just to make sure, your LSN(low speed needle)is the screw where the throttle linkage attaches to the motor, and yout HSN(high speed needle)is the screw inside the brass barrel, where the fuel line entersthe carb.. Just wanted to make sure!