The silverstone setup is very similar to my outdoor base setup other than I normally run the front link in middle hole with 1mm under the inner ball stud along with Xgear red rear spring and the 1.2mm ARB mounted ends flush with outside of ball cup.

Why 25deg castor, it's all about getting the nose in to compete with the likes of the KF2. Once the car is turned in maintaining steering through and out of the corner is all about roll centre tuning.

For the wet I normally drop the inside of the rear link to 1 or even 0 under ball stud, move rear shocks in 1 hole and raise the whole car a mm or 2. If it's really slippery then go to zero antisquat to manage sidebite.