How do I set up the backlash on the diff correctly, I'm sure mines a bit loose but I'm not sure The cars a 2wd Saph Cossie, standard casing with Quaife internals.

I've got to take the damn thing back out again in a couple of weeks anyway as its chucking oil everywhere

The underside of my car shouldn't rust, as the engines throwing oil about along with the gearbox and diff