gtr2 head shake, apex lookup, and world shake settings

[tahzib]

i am playing GTR2 with mouse (i am poor, sue me) and apart from the usual mouse snap during short S curves i am getting the basics down.....but what i really want is to know what level of head shaking should i use to get the realistic feeling?and also what level of apex lookup should i use to look at the corners without affecting my gameplay.....
helmet view is something i really came to like from Shift 2 and pCARS.....