I use retrofitted t8 LED fixtures in the cold seasons.I have 4 of them, 4 lights per fixture. They are 6500K daylight. They are on a timer set for 14 hours in the late spring and fall (mid spring through early fall, mine are outside) and 12 hours in winter.

As long as the hoya vines don't touch the lights, they are happy in these conditions. That being said, some of mine need more drastic differences in heat/lighting in the winter, to bloom. They get normal household conditions in a West window in the winter.

Man, I was reading about it today and I read a couple places that the lower the K, the redder the spectrum and this induces blooming. I ended up buying one 3630K bulb (kind of in the middle of 2000-6000K) to put on one of my small RHP's to see how it does.

Should I exchange it for a more powerful one? There's so much to lighting it's honestly overwhelming lol

Mine bloom fine under 6500K. That being said, they are also exposed to sunlight throughout late spring to fall.

I read that, as well, but I don't know if there is any evidence for or against it.