Hi David,
is there a need to use UV light, e.g. does the photoresist need UV to react? Blue or white light would not only be more friendly to the DMD chip but also require less precautions, be directly visible with a microscope for alignment and checking (or at 50u, maybe even a good magnifying glass), etc.
At least at 50u the wavelength will be much smaller so sharpness or diffraction isn't a concern.
If you really need UV, I'd suggest using a socket so you can at least replace the DMD chip when it breaks. 30-50€ is okay-ish to try if it survives "long enough" on average.
Greetings,
Martin