Hey, this is great! Someone that's been paying attention to advice! [X(] [8D]

They've been tuning engines since before tachs were around, so yes, someone devised a couple of real clever ways to determine the best needle setting.

Here's my favorite:
Start your engine again, and since it sounds like it's set close to right, give it full throttle and raise the nose of the plane to at least 45 degrees. You should hear the rpm's increase. If they don't increase, or the engine sags or quits, then you're already too lean.

If you Do hear an increase in rpm's, you can lean it a bit more and try again. When you reach the point where the rise in rpm's is small, then back off about a 1/4 turn. That setting will ensure that the engine is lean enough to run well, but rich enough to handle the way it leans out a bit in the air as it unloads, and leans a bit more as the tank gets low.

The second method is to get to full throttle and "pinch" the fuel line just before it enters the carb. You should get similar results to the method above. I prefer the above because I've found it a bit more accurate.

If the engine was stumbling at the transition between idle and quick full throttle, then the low end (if two needle carb) would be a bit rich. If it just died, the low end would be a bit lean. (Same is true of the air bleed carbs, except reich and lean adjustments are backwards because you're adjusting air instead of fuel. )

Welcome to RCU and Good Luck with that maiden flight.
Dennis-