It sets the steering limit; the maximum you can turn the wheel. Around 32°.

The "caps" it refers to are also called "anti-groan" caps, which reduces noise when the suspension flexes with the steering turned to the stop.

 

My caps are long gone and I have worn a nice groove in the steering stops for a little extra tight trail steering ability.

 

Im confused a little here, you said "#8 If it pulls to the oncoming lane, decrease the caster on the driver side, if it pulls to the passengers side, increase the drivers side caster."

Everything I have read shows a negative caster pulls. So if you are pulling to the left, and you decrease the caster on the driver side it would pull more to the left.