Question on factory rear sights.

[FF1063]

What is the standard rear sight number on a 75B 9mm?
The CZ USA site is not very clear on how high each sight is or which one is the standard.
http://shop.cz-usa.com/C-125/FULL-SIZE.aspx

My new 75B 9mm was hitting very high when I got it. I managed to file off enough from the top of the rear sight to get the point of impact down to about 3" above point of aim at 25 yards with 124 grain ammo.

I'm ordering a 5.5mm high fiber optic front sight from the custom shop and would like to know how the numbers work in case I want to change elevation.

[1steelshooter]

I think both my 75 sa and my compact came with #4 sights. You have to look at the underside of the sight to see the number. If I remember correctly each number is .010" taller than the number before. Here's a formula for figuring out sight sizes. http://www.dawsonprecision.com/images/Instructions/FrontSightHeight.pdf