Sounds about right. 300 front, 550 rear

You want it stiff at the back to help nduce oversteer. The stiffer it is, the less progression you get from grip to slide.

For full monty track set up you should look at how much bump steer you have at the rear this also dictates how stiff it should be and your static toe setting.

Its a huge subject with very many variables. There is no such thing as a perfect set-up. You just have to work out where to take the biggest compramise.

S.