Sounds like heat may not be much of an issue for you then. My BC does sit in the warmest room in the house so that doesn't help but for a while it was a struggle to maintain it below 82. I finally just dropped the temp on the first floor lol!
If you go DIY go with greater color spectrum than just blue and white. It'll cost more if you want the ability to control more colors independently but I think you'll be happier in the long run. There are also people on the board who can custom build lights for you. Again, from my experience, go with something more than just royal blue and cool white.
As for fixtures there's a ton of choices out there. They have dimmable Kessil's now, rapidled even has a fixture, and then there's always the overkill of pacific sun Triton, AI, and Ecotech among many others. I say overkill because it would be a ton of light for a BC. But they'd be great lights to move over to your 90 at some point as well.
