If I use a GCD weapon skill and immediately activate Stardiver, the skill won't even start until half way through the GCD and the animation ends briefly after my next GCD window. No matter my timing, it always clips when I single weave even with great ping, running @100 fps etc. My gcd is 2.39 which is a bit fast but really Stardiver animation should be sped up and shortened by about 15-20% to make it smoother. Basically, if you make it as many frames of animation as Dragonfire Dive, it should be perfect.