Sights or no sights?

[SIMBA-LEE]

Didn't your DD upper come with a rear sight? I recently bought 2 of them from separate locations and both came with a DD rear sight.

It's not the best choice, but it's good enough for now. I'll add a Troy BUIS later.

Sounds ok to me.

[SIMBA-LEE]

HOB correction for irons vs RDS set up for absolute co-witness would be the same (likewise the cheek weld position). If set up to co-witness in the lower third, the difference would be 7mm (about 1/4 inch) lower for the irons. I can't see the need for a cheek piece for 1/4 inch. I can't speak to scopes...never had one on an AR.

I agree about the need for iron sights on a civilian-use AR...superfluous. But the OP is going to start with irons, so that doesn't apply. He's better off IMHO with folding Troys or MBUS.

With the co-witness set-ups you described you are correct that a cheek pad isn't needed.