That RBIZ is much too complicated for my tastes. Dug up my old rifle range manual and found the steps for doing a BZO. It's for the M16A2/A4 using iron sights, but since it uses the 300 yard setting it should be usable on any kind of sights if they are the same distance off of the bore centerline. Obviously we were using green tip bullets, forget what they're called but you can probably google it.
The short version is, set up a target at 36 yards and dial your sights in for 300 yards. At 36 yards the bullet will cross your LOS rising, and at 300 yards it will cross your LOS falling. Effectively sighting in your rifle for a 300 yard Zero using only a 36 yard rifle range.
If the rifle is shooting high or low, make the elevation adjustments on the front sight.
Move post clockwise to raise shot group.
Move post counterclockwise to lower shot group.
Windage adjustments are made on the rear sight.
After that whatever you put the sight setting on should be where it shoots. 200 yards 500 yards etc. My A4, which I have the shots marked for in this log book was right on, but my old A2 had to go a click or two up or down at 500 yards to be exact. Hope this helps.