I'll bet you can easily see/sense an 030 difference in sight alignment, if that's the correct trig (I have no idea). When the sight tops aren't level or when the side spacing of the post in the notch isn't equal, it doesn't take much to see it.
The "very steady" factor isn't nearly as important as the "press the trigger at the right time" factor. ie, your sights and gun can weave all over the place. Only thing that matters is where the sights are lined up when you send the bullet.