Now that I have some roth hybrids in sheath, I would like to add my two cents in the discussion.
First off, regarding light, I doubt multis need particularly strong light. I know there are a handful of species (multi or not) like glanduliferum and druyi that grow almost completely exposed in the sun with some grass growing all around them but not providing shade over the plants.
What little in-situ pictures I have seen of things like stonei, roth, anitum...all look very much typical of many other paphs that grow on rock surface with tall trees shading them with breaks of sun light coming in from canopy here and there. Some time during the day might give them more of less direct stronger light depending on the location.
There was this report that philippinense from a certain island were strangely yellowish and I wonder if this is one of the sources where multis = a lot of light came to be??
I have seen nurseries growing multis along side other types of paphs just fine with dark green leaves and lots of flowers.
Ok, so my limited experience. I only have just a few because these plants tend to get big and take up a lot of space. Plus, they are not my preferred types of paphs. I got myself some seedlings to try my hands on just out of curiosity. Also, a generous member on this forum gifted me one Wössner Black Wing. The others I have are Lady Isabel x anitum and Saint Swithin x anitum.
I had them on the windowsill under natural light initially, but since about four years ago, I moved them under T8 set up. Typical florescent shop light stuff, not specifically made for growing plants. I have two 4ft tubes per shelve hanging over the plants with about 8inch (or more) distance between the plants and the light. Plants were initially rather small, not tiny, at about 4-5inch long leaf size.
They grew slowly for the first three years or so, but then in the last couple of years, they started to get noticeably big. All three of these are now as big as my arms length from tip to tip. I don't fertilize them heavily. Mostly just water with occasional dilute feeding.
Now, they are all sending up a sheath with a new growth of their own.
Funny thing is two of them have never been repotted this whole time and the small (2.5in tall pot) pot is full of their roots and some roots are coming out over the pot. I plan on moving the plants into larger pot for stability. I would hate to break off the emerging spike after all this wait.
The color of the leaves on my plants are pretty dark green. Definitely no hint of yellow at all.
Ok, that's about it.
If they bloom out decent, then, I will share the photos on the Paphiopedilum section on this forum.