I'll run all different settings myself. Depends on the terrain. Rocky terrain demands at least a 1/8th turn loose. On really nice gripping terrain I'll slam it tight then back off just a HAIR.
The more slip, the less power to the wheels. Consider it a constant clutch that you're slipping. The more slippage, the less power to the wheels. This gives the tires the chance to bite where they usually would just spin.
NOW, a fully tightened spur will give INSTANT response, and easy wheelies with a properly tuned mill. However, this stress is transfered right to the differentials. The drive train is light; and tires are the heaviest objects. So, if you're running high throttle and pulling the motor at wide open in a jump. One landing at full throttle will snap something. All of the engines power (somewhere between 2 and 4hp) depending on the mill, will be directly to the driveline. Hence the weakest spot, dogbones and diffs. Usually the dogbones will twist, but the diff will just disintegrate. This is a bad thing. It takes practice, but you CAN run full tightened if you learn how to work that throttle and brake. I've actually seen stripped diffs (well broken teeth) from braking too hard with a landing.
Either way, it's simply up to you, I suggest running an 1/8th turn out until you learn expert throttle control. Then, and only then would I start running tighter. 🙂 Good luck and have fun with it!