Badger, go read this thread from start to finish: Cheap LED Strips : A Viable Alternative
But the last few dozen posts really sum it up. You can refer to my most recent posts for the latest info and videos that describe what’s going on. This one and my post before it as well give a good baseline on the current state of research into cannabis lighting done in public labs, not done by lighting companies who are biased:
You don’t need high color temp to veg, that’s BS. You’ll want to unlearn all the weed growing conventional wisdom you have read or been told over the years - they’re mostly all myths with no basis in fact or science, often created by people selling products or selling their image as know it alls.
It’s mostly about the ratio of the colors output by your light. Blue makes plants grow slow and small. Red makes them grow big and fast. Too much of either is bad. All modern white LEDs from Bridgelux, Samsung, Osram and Nichia contain plenty enough blue at all color temps between 3000k and 4000k to effectively veg and flower weed (don’t trust any other manufacturers of the diodes, and don’t trust brands that market themselves all over the place - especially not the purple or pink spectrum light manufacturers).
But we’re just in the infancy of being able to study the effects of very specific light spectrums on weed. There’s no proven benefit to adding UV or supplementing anything if you use LEDs from the mfgs I mentioned above in the color range I mentioned. They will grow phenomenal weed from seed to smoke.
And you do want to vary light height and keep the type of lights that @Vagabond_Windy built a max of 12" above the tops of all plants. You lose half the light that your plants use to photosynthesize at every doubling of distance from the canopy, and you lose 15% to wall reflections no matter how shiny your walls are. So you want to try to train your plants to be roughly the same height and keep LED strip lights as close as possible to the tops. I have some that are 3" from my old COB LED lights right now and they’re doing great.
If the plants seem to suffer, instead of raising the light you’re better off dimming them to lower the intensity - you use fewer watts and don’t lose the intensity or waste photons on wall reflections like you do from hanging the lights higher - this is why extra high intensity lights from a few point sources above your canopy are a bad idea compared to distributed lighting across the whole canopy from LED strips. And light intensity will have an effect on keeping plants short, to some degree. With all other variables being equal, the majority of plant height in veg is dictated by light intensity, heat, their genetics and how they react to your light spectrum. In flower, it’s almost completely heat and genetics.
As for keeping plants short, I address this in one of my posts above. Summarized version - like Herbie mentioned, you don’t actually want stocky plants for best yield unless you are restricted to really short ceiling heights.