On most engines, the High Speed Needle sticks out, from the carb, generally pointing diagonally upward (usually near the fuel line). Although, if you had to spin your carb 180 degrees to get the slide to line up with the servo, your needle may be pointing diagonally down.

If you only have a two needle carb, the Low Speed Needle, this needle will be on the side of the carb closest to the exhaust pipe. If you have a three needle carb, this needle may be on the side closest to the servo, and the Middle Speed Needle (may not be right name?) may be on the exhaust pipe side. Although these may be switched from my description as well. You really need the manual for this one.