The wheel pants' center aft end must be aligned perfectly with the tire's centerline, and positioned 8 5/8" above the floor (aircraft lifted and level). I created billboard-style reference boards with an exact centerline drawn all the way around it, front and back. I then marked and drilled a reference point exactly 8 5/8" up the front face: The hole will allow a small length of piano hinge pin to stick out.
I then drilled a #40 hole in the exact center of the wheel pants' center aft end. With the pant in place, and the billboard sitting on a tire center reference line, I can stick the pin into the wheel pant center aft end hole, thus perfectly aligning the wheel pant on center and in height.