Some are saying reds should be run through the early stages of a plants life.
Accepted thinking was that reds helped with the stretch and flowering but this is now being questioned as the most current research indicates that it assists most in veg....but the research is.not conclusive. I'm sure it does help in flower and stretch.
I run my reds, 30w x 5, 660 & 730nm, right through flower on 12/12 from the flip. photoperiods of course.
Some run reds through the dry also.
So the answer to your question will also be dependent on what other lights you are running, at what height and for how long. This will determine what works best with your reds.
Experiment