I tried Takatoy's shoulder mods, had no such luck. I ended up with a big ass gap and got nervous of removing more before the grey plastic piece falls off.
Takatoys- Did you also shave off some of the grey plastic part too?
promethuem5 - I sort of dive into it, and rather then sanding the tab down, I trimmed it. It's alittle lose when in fighter mode, but still holds fine. Transforming it, effortless