Use offset bushings if you need or want more negative camber or positive caster than you can get with standard bushings. Most people can get what they want (a little negative camber and a couple degrees positive caster) with one offset bushing in the rear of the upper control arm with the offset hole towards the ball joint. This effectively shortens the rear leg of the upper control arm. If you look at the picture you can see how this works. By the same token adjustable strut rods allow you to adjust caster with very little change to the camber.
If you want a lot of negative camber then use two offset bushings per control arm, again with the hole towards the ball joint to shorten the effective length of the control arm.
Our cars do not need much positive camber to have excellent stability. The steering axis inclination built into the spindles handles that. In fact the manual steering cars were aligned with negative caster to make steering easier.