Diffs easy to adjust. Just find the screw head and stick a driver in ther to hold it and turn the opposite wheel to tighten or loosen it. The screw head should be on the left when looking from the rear though otherwise you will need to swap it round to stop it coming undone. Then just turn the right wheel clockwise to tighten and anti to loosen it.
For how tight that's a bit hard to explain on here, just needs to spin for say a half to one second and it should be good, or till it stops making the noise
For the gearing best Dan or Chris answer that as I'm not familiar with the Novak stuff....I like to go fast
