[juchong]

There is enough slop in a kitbot system that you're very likely to overshoot. We created some autoaim code similar to what has been posted above, which is what I'm referring to.
On the topic of the servo, a servo works by providing position feedback. This same idea holds true for a larger system(such as a kitbot) which also requires feedback. You may be able to get the system to function by adding a bit more dampening (carpet) but it won't perform well enough to accurately aim.