When learning defenses and the offense of a grab, grab like you mean it.
Too many times I see grabs that are done specifically to allow the good guy to win – that is more than ok when learning and first experimenting of course.
It is more than ok at teaching speed and power, of course.
But sooner or later, you MUST practice against proper grabs and practice doing a proper grab
HOWEVER, Like I keep saying, if you can grab him, why not hit him?