I'm so glad you've enjoyed the books! Grow lights are a great investment in the life of your plants.
Succulents have growing and dormant periods, just like other plants. Winter is often the dormant season for most succulents, and therefore require less light, but indoors they will still generally take as much as they can get.
When I've used grow lights for my indoor succulents, I usually leave them on for about 12-14 hours, mimicking the natural daylight plus a few hours. You want to mimic sunlight as much as possible and make sure to give them some “night” time without any light.