Just a thought. The big sights are obviously to see the sight quicker and easier. I was told by the manufacturer themselves that you will give up a bit of precision to gain faster sight acquisition. So, one, you won't be quite as accurate with them as you would a conventional sight, but you purportedly will be faster at self defense ranges.
Second, if you point shoot out to 21 feet, the large sights would be detrimental since they would be a distraction to your eye, and past 21 feet, you'd probably be better of with the precision of more conventional sights.