With too much you'll wheelspin more, and unless your car rolls like a barge, you wont get the full benefit of say, 3.0 degrees, as in the bends the tyre contact patch will still not be optimal. 1.5 - 2.0 Is fine. I try various amounts and see what it does, but if you don't have the know-how/kit to measure it then best stick with the garages settings.