I have Trijicon nightsights on all of my non-optics ARs (and nearly all of my pistols).
[img]www.bushmaster.com/shopping/scopes/Images/cp-25f.jpg[/img]
The Trijicon front sight only has the tritium vial visible on one side, but that doesn't pose an elevation problem because of the design. The sight post is two pieces, so that the top part will swivel in relationship to the bottom part. It has TWO notched adjustment discs, one attached to the threaded bottom half, and one attached to the top half. The way it works is, you adjust elevation by turning both halves, then you rotate JUST the top half until the tritium is facing you.
[img]www.bushmaster.com/shopping/gunsmith/ray-005.jpg[/img]
In order to do this, you REALLY need to use a sight adjustment tool, and to use it, you'll have to modify it first. The standard tool assumes a thin square front sight post, and leaves just enough room for it. The Trijicon post is actually rectangular when viewed from above, so the tool won't drop down low enough for the teeth to engage the adjustment notches on the post. I fixed this by drilling all the way through the center of the adjustment tool. Took about 5 minutes, and the tool works just great now.
-Troy