OMB, I'm planning on running 6500k in my T5 system untill a little past half way in budding before I switch out to 2700k, only to reduce stretch to keep mine small. But... I am underlighting with reveal cfl's 1200 lumens ea, 2500k. I don't mind stretch in the lower branches/buds, actually want it to bring them up & out to receive both lights. This will be especially beneficial to me, because I hand pollinate the lowest 2-3 buds on my girls, & I want the plumpest, healthiest seeds possible.
-- Many growers are using MH or 6500k T5's through budding to keep buds tight & compact. It's kind of a new trend, & makes perfect sence to me. But I am switching out to warm lights toward the end for trichrome production & ripening. Another thing about the CFL's. Did a little research & found them to put out more uv than any other fluorescent. BIG aid in budding & ripening! & get this.... been reading a lot of research reports from big universities, & it would appear that for tiny grow areas, the set up I've got going will be more productive than the lower watt HID's I'd have to use in such a confined space as mine. So I'm pretty happy with what I have for now
-- So there's a bit of debate going on about cool vrs warm lights in budding. So I'd say for now, lets call it a personal choice. Cool lighting = smaller, tighter buds. Warm lighting = bigger, fluffier buds. Warm underlighting is my own personal twist on the cool light budding thing.