NADCAP AC7114 is a pretty good guideline for UV inspection.  The problem is that the longer wavelengths encroach on the visible light spectrum and can cause glaring issues.  For conformal coat, not so much, but the 365nm (UV-A) wavelength is the recognized standard and the standard which optimizes fluoresence.  I do believe that there may be a good compromise of adding a UV-A Pass Filter.  Magnaflux, OMEGA Optics, or Edmunds Optical (probably others, these 3 come to mind) for purchasing these films/filters.