I would say the like the cooler temperatures more then less water. Grow rocks don't hold much water so it does not take that long to dry out. Check under the pots every once in a while. In Ebb & Flow you can get a slimy bottom that can trap water. A good wipe every week or so is advisable as preventive measure.

What temperature are the plants under during the light cycle?

Don't laugh but I know hundreds of growers who grow Ebb & Flow with grow rocks and they water 15 on 45 off even during the dark cycle. Each strain is a little different that's why we keep notes and journals for our plants.