The epoxy pads I had injected into the wheel pants last night were cured, so I popped off the front half of the pants and built up an epoxy pad for the axle extension. This gives the axle extension a good solid interface to the wheel pant. I just had to wrap the extension in packaging tape and wax up the screw with some turtle wax, and then I slopped in some flox. I also cleaned up the wheel pant bracket pads where the epoxy had squirted out more than it needed to.
Then it was on to fitting the right side wheel pant. I followed the same procedure as the left, but this time managed not to smash any more fingers. By the end of the night, I had the pant aligned and the epoxy injected.