I'm amazed at the fast progress on this one. Great to see progress, and especially a bit of information on the technical problems and solutions that have been found.

With the calibration, I'm wondering whether you could do something like have a printed grid in the build container, point a webcam at it, and then refine the laser positioning automatically until it can follow the grid. No need for any human interaction, apart from placing the grid - and this also makes re-calibration trivial.