Another disadvantage being that your distance between the mirror system and the target must be fixed the same each time you setup.
This isn’t an inherently bad thing. As a marketable product this would imply a one-time manual alignment for all 48 mirrors but cheaper lifetime maintenance costs.
If you were going to sell a kit, having 48 sets of 3d printed mirror mounts of the right length for each position wouldn't be out of the question. Just a screw-on clip with the right length standoff for each mirror corner would be all you'd need. You could conceivably have different sets with different focal lengths.
I don't think it would be too fiddly done that way but it might take some work to make fine adjustments straightforward.
This isn’t an inherently bad thing. As a marketable product this would imply a one-time manual alignment for all 48 mirrors but cheaper lifetime maintenance costs.