Surprisingly, I only have trouble with the 2nd GK. That's a hit & miss; You have to use BOTD -> B4B starting 1/3 - 1/2 through the GCD. The other GKs are perfectly normal, as you're stacking up to 30s so you can blow x2 GKs together closely, which always come after a "4th". Selene however, should fix it.
As for a Raids, if I had the gear, I'd definitely test it at some point to really test it. I'd definitely expect you'd need Selene uptime with Fey Wind and your BOTD timings will definitely be stricter. It's definitely worth looking into. Even if 490 is the far extreme limits you can push, 520-540 is also a perfectly good SS to aim for, with decent oCD placements.