Bolted up the rest of the z-axis linear motion components including the spindle, configured all the electronics and software, and did a successful dry run. The stepper driver board that I had installed was bad, but thankfully I had an extra. In the future, the x axis motion can be extended slightly, and the z-axis downward limit switch is around 45mm beyond the feasible range of motion, so if that is to be used, some alternate stoppers and limit switch mounts will need to be printed.