DVLDOG, where do you shoot at??
At PI in bootcamp, and at the range at Cherry point, we zeroed our weapons at 25 YARDS (on Firday of Snap In), with the sights set at 8/3, making all adjustments on the front sight post. Then on the first day of the shooting on Monday, we BZO at 300 yards on the Dog target.
I have shot expert using this set up, mad a possible at both the 200 and 300 yard line (not on qual day unfortuatly) and got 9 out of 10 in the upper center chest at 500.
So it would seeme to me that this method is the best (at least for the shooters at Cherry Point).
Also, most AR's don't come from the factory with 8/3 -3. My Bushy didn't, so you will most likely have to retime your sights yourself.
If you have to, run your sight UP until you can get to the set screw. remove the set screw(it should be AFT of the windage screw by 1 click), and run the sight down all the way. Then turn the UPPER part of the elevation know until you can set your elevation to 8/3 -3 clicks. It only takes a few minutes to do this, but be careful that yo udon't stripp the threds in the upper dial of the elevation knob. Use an allen key to line up the setscrew hole with the lower hole so that you don't damage the upper elevation knob, or the set screw.