I use the one that gets the tire away from the body the most with the 4.0 wheel.
I have run ones that put the tire closer in the front. I did it for short course racing thinking it would help in the tight turns. It seemed to work good. But also rubbed on the bump stops pretty good. I would not trust it in a long race unless I adjusted the steering stops. Also it could affect how it fits in your spare tire mount. They wont fit in mine. So I stick with the same.
michaelbrenner replied the topic: Quick wheel question
I have recently measured factory VW wheels that are 4" wide. These wheels have a a 4-1/8" offset from wheel mounting surface to inner rim lip. 4.5" wide wheels were 4-1/2" offset to same inner lip. Conclusion: narrow wheel makes tire taller and bulge wider; 3/8" offset difference of 4" wide wheel puts tire slightly further outward, further from suspension limiters but also closer to the fender lip Oh wait, you can't run a 4" wide wheel, rules do NOT include 4" wide wheels!!!