Don't cut off fan leaves until the plants vertical growth has stopped. You don't want to stress the plant while it's still growing. Just tuck away the leaves under other leaves. In the last few weeks, once the plant has stopped growing upwards you can cut off some of the fan leaves blocking the main cola. Be sure that you never cut away 50% or more of the fan leaves.
I have found that that first ( and I have no idea how old they are) you are going to see some leafs giving way to new as your plants mature you will look at this as a non issue
Yup, that right there is a picture perfect time to cut some fan leaves. Only cut the leaves blocking your light though. I cut back the large fan leaves blocking my cola and got 2 42w CFLs right up against the sides of the cola and my side girth exploded!