There are 2 seperate adjustments to the center shock
1 Oil. Controls the front to rear grip bias.
Light oil--> balance to rear (more rear traction)
Heavy oil --> balance to front (more front traction/steering).
Best use a very weak oil with a softer front tire compound, for example a magenta instead of a purple for more overall traction instead of heavy oil and a hard front tire.

2 Spring. Controls on and off power steering.
Stiff spring --> much on-power steering, little off power steering
Soft spring --> much off power steering, little on power steering (less spinouts coming out of the corner