Maybe try reading some of the Caffeine threads we have going here?
@Chiron created a really good one recently that I’ve been following 
Ironically I’m actually drinking pre-workout right now lol, but I do use it only once a day before I workout.
I’ve been trying to manage my caffeine intake also and it can be a huge bitch, especially for those of us who have problems with moderation. I noticed that I started drinking way more caffeine after I stopped drinking. I’ve capped myself at 400mg a day and I don’t go past that. It seems like a good balance right now because I still sleep fine, but eventually I’d like to reduce it.