How to Dragoon Per Second: A DPS Paradigm

[Greyfrost]

Alright, I've rewatched Dervy's video for the Advanced Dragoon rotation guide many times.

I still can't figure out how Dervy managed to double-weave oGCD without clipping even a 0.1-0.2s into the GCD.

I was able do it once or twice, but I will clip a splitsecond into the GCD. Is it the button mash? Is it the timing of the buttons pressed? Or maybe latency (I doubt this)?
Not feeling very confident about my double-weave.

I will try and upload a video, I hope you guys would be willing to help.