Think of your fan leaves as solar panels. They catch all the light and turn that into energy. The energy created by them goes into the buds. If your 4 weeks into flower, your plants are done stretching anyways. Now they are just going to start fattening up. So don't cut off those fans and don't trim them.

It would be like me cutting off your big toe and telling you to run faster.......not happening.

Tuck, tie if you want. But don't cut off my big toe.