Well if you have UVB then you also need UVA as this induces UV photorepair. But UVA/NUV alone also works to some extent as there are many absorption peaks sitting around 365-420nm. Actually most peaks reside within these UVA/blue bandwaves....
FR can be tricky as the plant's physiological reaction is three-fold - if one encounters too much stretching under continuous daylight FR addition one has to either increase the amount of 660nm, and/or UV/blue. FR is a very special kind of light that disperses rather like IR, that's why it can also reach deep into a thick canopy. It may be used to increase photosystem I net photosynthesisrate as this is oftentimes the limiting factor due to the fact that the PSII supercomplex is twice as large as PSI in landplants.
Consequently, alot of new LED board manufacturers increasingly add this wavelength - citing the extended Fluence PhysioSpec here as a prime example.
As for the sleep initiation - Cannabis is a plant that can respire during the day (= it can be lit 24h/7 "without problems") whereas, for example, tomatoes will encounter photoinhibition up to the point of photodeath if kept too long under strong continuous light.
Nevertheless, the "Florigen"-mechanism is still not completely understood so it remains debatable if an increased length of night brings benefits. Oftentimes, the answer to such a question is not easy as a grow consists of many interrelated factors...
Paradoxically, there emerge new insights into "breaks" of the daylight regime, ie. giving plants a short time of darkness or reduced irradiance without the sacrifice of biomass. This may be explainable from the relief of otherwise toxic photosynthetic byproducts (radical oxygen species) by a superoxiddismutase-clearance mechanism which is increasingly necessary at high PS rates (close to the CO2 cap)
Not so long ago scientists found a new type of chlorophyl (Chl-f-712) [IIRC] in cyanobacteria & green algae which enables uphill-exciton-transport to the reaction center of PSI (p700). This is very unusual considering the typical buildplan of the light-harvesting complexes which hold the absorption-max pigments at the end of the chain (p680 & p700) with the other, less red-shiftet pigments increasingly distal to it (the increased latent energy of shorter-wavelength photons help to overcome the distance....)
I'm not aware if this Chl-f can be found in landplants as well but the PS capacity of FR light beyond the "red-drop" has been confirmed empirically since 1957 by Emerson (et al) many times.
So this region of the spectrum is still not fully understood and perhaps harbours unknown potential. We'd need to have a team of experts to
systematically review this particular region, as isolated studies may not get to the true bottom of this, plus, some are even in conflict, esp. when it comes to increased or decreased measured PS rates.
P.S.
btw it's good to see you're back, and (hopefully), in good health.