If I was to use a dovetail mount on my Glock how much higher up would the red dot sit compared with getting the slide milled?? I thinking of putting on a fastfire on a Glock 19. I have heard that it would only sit up 1/8 to 1/4 inch higher using the dovetail mount. If that is all I can't see were it would be a good advantage getting the slide milled. Is the distance about right?? I can't see that it would affect your speed given how high a red dot sits on a race gun. Whats your thoughts?