warm grow lights with a 2700K output are supposed to be used in conjunction with full spectrum but the warm spectrum promotes fruiting and flowering. Would this have any effect on citruses? Or would it be just a waste of money?

"Warm" light is the red spectrum. As you probably already know, "warm" light has nothing what so ever to do with temperature. Because citrus only bloom from some form of stress, usually low temperatures, or drought, the purchase of a red spectrum light would be a waste of money, especially if you already have a full spectrum (red & blue) light. - Millet

Thanks i thought that was the case.