Yes, Photographer sets exposure to -6.64 (guessing its from 6 2/3 but) when doing sunny 16. Going up 6.64 to 0 (approx office lighting) that corresponds to a 1" shutter and my darker than an office living room shows up darker than an office. So I don’t think it is too far off.
For something I just tried to help out with, not my stuff. But here I apply sunny 16 to characters and in frontal sunlight they look “correctly exposed” (not perfect, the idea is that you can’t go completely wrong, compared to camera light meter that can do all sorts of things - kinda). Looks about right to me:
For fixtures, it’s just messy. I have to create analytical light in one room, do the lumen via 683 scale on it - and similarly, I don’t know if it’s an accurate conversion. Then adjust the mesh light in another room until they match. We can get weight using rigid body, but not surface area (that I know of).
And then there is fresnel lamps. But for spots we can’t override the falloff when we reduce the cone angle. I get it would be annoying having to deal with it for regular art stuff. Not that I ever use them practically, but it would be nice to have if the situation comes up.
683 (or my 666 :p) is as far as I understand it, lumen to (blender) watt. No efficiency/efficacy involved. Luminous efficacy is for dealing with light sources that doesn’t have a lumen given, like a 60W incandescent light bulb. But I could be wrong. I’m no expert in this, and it confuses the living daylight out of me. Who thought using watts could be confusing when old light bulbs deal with a completely different kind of watt?
And of course, the manual doesn’t state anywhere how to setup a scene using physically correct values, or at least physically correct relations.