I realise that sometimes an adjustment may not work as per a handling guide, but I've found that some guides (not yours btw) completely contradict each other.
When talking about caster and roll centres, I know that there are 2 guides (XRay and Losi) which have 100% opposite views on how they work
Theoretically, any adjustment should be consistant from car to car, it's just odd that there seems to be no definitive right or wrong answer.
It's a bit of a problem for people like me who know how to get a decent set-up quickly, but then have trouble extracting those last few tenths out of the car. In my case, I sometimes can't even feel some of the changes I've made
Anyway, as suggested by the guys here, I've got several things to try next time I race.