Take this post to the [i]Competitive/Accurate AR15[/i] forum, and you'll get a few good responses as well.
But yes, may your own judgement be your guide. Plus, weigh the disadvantages against the advantages: one - sight- one - sight will give you better INCREMENTS for adjusting, but what if one of those shots was a "stray"?. Two shots - sight will give you better GROUP adjustments, but allow for less pinpoint accuracy. When it comes down to it, shooting consistent 9 or even 10 groups are (in my humble opinion) more important than having half 10's/ half stray shots. All depends on your judgement, marksmanship, the ability to group shots well (my biggest problem), AND whether you're shooting Service or Match, etc.
Very good question, thanks for posting it!
Jewbroni~