Currently running 10thou in the front and 5 rear for worksop.
I was suffering front chronic understeer, and kept going softer than everyone else on front springs. A bit of help from Adam, and it turned out that running it like that wasn't making the tyres work properly. So stiffened it up and took all the weight off, and bingo! Sooooo much better.
Strange but worth a try.
The pendulum effect is the main thing.