Spacers are going to depend on what offset your wheels are, and track conditions.
"As an example. use a 3.5" offset wheel at all four corners of the car. When the track is wet and tacky, use a wheel spacer at the right rear to move it out. When the track gets to "normal" condition, take the spacer out of the right rear. When the track gets dry/slick, install the spacer at the left rear to move it out.
On an asphalt track, wheel offset can be used to offset the car over the car's track width 1- inch to the left to gain more left side weight distribution."
("Dwarf Car Technology" by Steve Smith)
Hope that helps you somewhat.
Steve
