If you're not maxxing out PPFD with your main grow lights, adding more light will help because crop yield increases an almost linear manner as light levels increase.
Blurples make/made it hard to see the plants and, since they're earlier generation diodes, they're not as electrically efficient as newer designs but more photons will get more growth, up to the light saturation point.
As you've posited, fire up the extra red channel. The more red the better. Red photons (660nm) don't have any special impact on plant shape but the diodes are very electrically efficient so, yeh, go for it.