Questions about flowering.

Should I let my coco medium dry completely before I switch to 12/12?

No just keep watering as usuall.

Well watering has been messed up. The roots haven't been soaking up the water well. It's been taking 5-7 days before the medium is dry again. I've been watering 6 3gal pots with 4 gallons and I'm starting to think that's too much. Advice?

They are big pots you have there and a good way to judge your watering in my opinion would be to drill some holes near the bottom of the container (drilling at 4-6 spots around the pots). Then water slowly around the edge of the container untill you see some water or dampness showing through your container holes.