2 things:

1. If you want to do 3x FC manually, you should go SE -> SE -> BB -> SE (or just 4x SE). If you go SE -> BB -> BB -> SE or SE -> BB -> SE -> BB, Eye will fall off and you'll be at a PPS loss.

2. Fey Wind is on a 60s CD, Berserk is on a 90s CD. Fey Wind lasts 30s. Your second Berserk won't benefit from Fey Wind and you won't be able to get in the 9th GCD if your SS is too low. You want 470-500+, depending on ping, to reliably nail the 9th hit without Fey Wind active.