Front End Alignment

[clemsonteg]

So I am working on the suspension of my 70 C10 after some changes recently and I am having a hard time grasping the concept of adjusting for caster. Toe and camber are easy, but the sources I am seeing online don't match up with the way by brain is seeing this.

From everything I have read so far, positive caster is what is desired and in it's simplest form, that should be the bottom ball joint being more forward than the top ball joint.

What is throwing me off is the adjustment for caster. Several sources online indicate that to increase caster, place shims behind the rear most adjustment stud, or remove shims from the front most stud. To me, that seems like it would push the upper control arm and the ball joint attached to it forward, not back.

Am I missing something?