The OP should be alright on CBC since he's replacing the UCAs, but maybe Metalworx don't clear as well as DK or PRG?
I think what Lax is saying is that at full droop, with the spindle and UCA articulated down, the "rim" around the ball joint touches the edge of the spindle on the rear (of the truck) side. That would happen because the UCA is swinging down so the rim sits at a steep angle to the spindle, which is still vertical in orientation. Maybe I'm missing it, but that's what I'm seeing in my head.
I think what Lax is saying is that at full droop, with the spindle and UCA articulated down, the "rim" around the ball joint touches the edge of the spindle on the rear (of the truck) side. That would happen because the UCA is swinging down so the rim sits at a steep angle to the spindle, which is still vertical in orientation. Maybe I'm missing it, but that's what I'm seeing in my head.