Importance of SS for DRG

[Shurrikhan]

I meant having my GCD around 2.45-2.48, but thanks for the info.

That'd be something like 404 - 479 skill speed? As far as I know you'll want at least 500, or a 2.44 GCD. Dervy did a proof of concept for 490 SS, but it still occasionally failed to meet the essential timings on its final blows within his HT windows, so another 10-25 would probably be a lot safer, especially if your ping is over ~80 ms.
https://www.youtube.com/watch?v=ZA3FMkr9UjI