Hey Michael,
I have not flown with Lume Cubes, however, we have mounted minor to extensive lighting solutions to our enterprise drones on a per project basis or as needed. In regards to MTOW, I have always updated relevant flight materials including Operations Manuals etc with whatever light solution we decide to put on, be it day of the shoot or a month before. Especially when it comes to night operations, cover all your bases in both current information for yourself and relevant parties (authorities, permits etc) and materials that could be presented in court.
It certainly is well received by our insurers, shows we are current with our information be it small to large details, and potentially offers a buffer between an accident / crash situation and my company.
Hope that's helps and is along the lines of what you wanted?
H