If you are running stock height tires ,the stock offset would be best,if your running short mx tires 4+1 would work best. Wheel offset has nothing to do with bumpsteer .from the factory with stock height tires the wheels have a slight amount of scrub which gives you a feel for the terrain and makes the tires some what self centering.4+1s with stock height tires put the tires in a neutral position with no scrub and no self centering ,some people like this feel. When running short tires 4+1s correct the change in scrub and put it back to were the factory had it.look up kingpin inclination and you may understand what Im saying.