I'm weird? This from the guy that buys a Modern Hunter, Swiss Arms, ACR, and whatever else I've forgotten you have but you never shoot any of them. Then dump hundreds of dollars on them adding lights and dolling them up so they can make for good pictures on here? You live on a farm, all your rifles should have 1000+ rounds through them. You should come visit more often, you'd actually use your toys.
It's not far enough back on an AR if you keep the BUIS behind it, not for me anyway. I run mine all the way back because I don't like having my stock fully collapsed to get the correct eye relief. It's actually pretty much the only complaint I have with the DR.
I don't think the DR designers gave a rats behind about being able to have BUIS mount under it. That may be why they built BUIS into the top of it.
With a quality optic there really isn't much point in running BUIS, the chances of an optic failure are pretty low if you spend the money on quality glass. Run Bushnell and BUIS are probably a good idea, run Elcan, Aimpoint, Trijicon, NF, etc not really any point unless you want to mall ninja co-witness.
The only use I have for BUIS is getting on paper first shot when I put a different dot sight on, besides that they stay folded, if I want to shoot irons I pull out my AR180 or M14. Maybe if I was doing 3-gun a set at 45° would be nice for up close but it's nothing a good 1-4 couldn't do just as well.