When to use caffeinated gels?

200mg caffeine tablet 45 mins before the start of an open TT & then a caffeine gel after 2 hours if the event is long enough (other gels, carb drink in between).
If it is just a club TT then just a couple of caffeine gels… 1, 20 minutes before the start, 1 ,10 minutes before start.
Works well for me.