I am still not sure on what upper and what optics to get for the AR. I know that I want either one of these uppers. Both has iron sights built into it. The big difference that I see is the height that the mount is on is different. I am not sure if I would want the higher or the lower one. Will that depend on what type of optics I put on it? What if the front sights interfer with the optics that I get? Do I need to get the higher one to ensure that the optics will go over the front sights? And will that mean that with the optics, the irons will pretty much be useless? Or do I just get something like the one below? (the flat-top) And not even have the rear sights and just use optics. And if needed, I can just a flip up BUIS later on. And one last thing, how will the height of the optics affect how I shoulder the rifle. I shot an Entry Tac with the removeable handle with only irons, and it was a bit awkward for me. Maybe I was not shouldering it correctly Thanks.