Vehicle is showing it's age and needs a camber adjustment. Which is the best solution for the front upper control arms? Small add-on adjusters or an adjustable control arm for camber?

 

Why do you need to adjust camber? My car is 15 years old and I'm still running stock control arms with negative camber from lowering. If your tires are wearing unevenly, you just need to have the toe adjusted via 4-wheel alignment. Camber is not the cause of the tire wear.

Is your car lowered at all? If not and you have noticeable negative camber, then you have bent suspension components somewhere, and the damaged parts should be replaced.