If you look at that behemoth update pic, there's a huge red plant on the side where there is hardly any light. Growth is slow, but color development is nice. Depends some on the plant. I generally just make sure nutrients are in good supply all the time. In otherwords, I focus on general plant health/growth, not reds specifically.
You can play around with dfferent color bulbs to get a different color for plants also.
Most of red in the color are anthocyanins, which are mostly carbon.........so seems to me CO2 has a dominate role there. Low N just means less Chlorophyll since Chlorophyll has a lot of N and limiting N=> less Chlorophyll. Which does not seem like a good thing to me personally, particularly if you bottom out on N, do not test much or test very poorly, have high light also.................
So there are risk associated with that, I think it's fine if you have low light.