Well, to be honest with you, there are a multitude of engines that fit the GT. Anything from an OS to an Ofna/Picco, all the way to a traxxas or a duratrax. Even the stock motor. These all have different needle settings.
Without knowing what type of engine it is, the best way to set it to factory is to set the high and low needles to 'flush', and the idle air opening to 1mm. This should get the motor started.
Next, once it's started, let it idle for a moment or so, then give it some blips on the throttle to clear it out.
Next, do some high speed passes. You're going to want good high speed with plenty of smoke. Check your temperature after each adjustment/high speed pass. Your target range is 220-230F. Anything below 210 or above 270, and you're going to wear out the engine before its' time.
Remember, no more than 2-3 seconds of high speed, or you could damage the internals.
Next, once you get the high speed needle in the ballpark, it's time to set the low end needle. This is done by letting it idle for about 5 seconds, then punching the throttle.
It should hesitate slightly, then take off.
Now that its' all set up, remember to clear out the fuel in the engine after you're done running for the day (attach ignitor, turn over until it won't start anymore), and apply afterrun oil. Just a few drops down the glow plug hole, turn over a few times, reinstall plug, and a few more down the carb, turn over a couple times, and store at bottom dead center (BDC).
Remember to always store the piston at BDC, and to NEVER run without a clean air filter.
Hope that helps, and welcome to the hobby! You'll love the GT; they're speed demons when tuned properly.
