No one is suggesting the wheel pants be aligned with anything on the ground.
If you were to take a vertical laser, and run it up the front of the tire over the top, aligned perfectly with the center line tread, and take another laser and run it from behind and up the top, neither laser is going to be level with the ground. That makes a pretty good reference in aligning the wheel pants because those should also establish a line that is lined with the wheel. In this picture, you can actually see the difference between a vertical line and the line of a wheel pant aligned with the tire/wheel.
My question is: If the wheel pant is aligned with THAT line (which, again, is a reference to a wheel/tire, not the ground) , how is it that line -- specifically the relationship with the line on the wheel pant and the line on the wheel, could change, given that the wheel pant is afixed to the wheel? It seems to me that the relationship between that line for the wheel pant and that line on the tire/wheel would not change at all in any configuration.
In my case, as you point out, the vertical line of the aft end of the wheel pant is not 90 degrees to the ground; that would be foolish. But it is parallel with the vertical line of the wheel.
If that is accomplished on the ground, how can the relationship between the two components, change with the removal of weight?
I can certainly see where it would if you aligned it with a vertical line in relationship to the ground, but that would be stupid to do it that way.
In terms of my lack of issues w.r.t the ball. True, I could have perfectly matched the two wheel pants and fairings (I didn't have any problem without pants/fairings), but that would be the first time in 11 years of building that I would have gotten two things perfect. :*) I checked the ball w/o pants. Installed pants, checked again. Lined them to the tire using lasers and checked again. The chance of both sides turning out exactly the same to negate the improper alignment of one another seems very remote. Especially since it zips right along w/ a fixed pitch prop.
I only wish I'd been as good on wing incidence.