Having had tritium sights (front and rear) in an AR, I’m here to ask you to please not waste your money. The rear sight is an exceptionally bad idea, because unlike a pistol, the rear sight on an AR is very close to your eye and the brightness of the tritium that close to your eye will wash out your ability to look through the peep and see the dimmer front sight.
Likewise, having an illuminated tritium dot on your front sight does not make you fast like a red dot would, and you’ll still need a light to identify/see your target.
As far as a recommendation on sights:
If you’re never going to have optics, get fixed sights. I think the Daniel Defense sights are great and are priced well, too.
If you’re only going to have a red dot and you don’t mind a co-witnessed sight picture, same recommendation as above.
If, however, you think that you might like to have magnified optics, or, like me, you don’t care for the co-witnessed sight picture and only want to see the dot, go ahead and buy folding sights on the front end. I don’t so much buy into the “folding sights will break 'cause there’s more moving parts” argument IF you buy quality on the front end (KAC, etc).
I ran a set of folding KACs in a Vickers class and had no issues whatsoever. I even shot cleaner and faster than a lot of the guys runnning RDS’s.
Finally, to echo what others have said, avoid the HK style front. All you need to worry about is a consistent cheekweld. That will determine proper positioning of the front sight post inside the rear ring. Don’t try to center the HK ears in the rear ring. As Rob has said, it doesn’t work so well with AR sights b/c only the front post moves, not the whole sight.
