I personally think that A1 with a2 small hole / large hole is better choice for combat rifles no knobs to fiddle with or up. Set it forget it... Works best for probably 99% of that Canada got it right.... IMHO. Now for the 1% on KD range or Camp Perry go for it. I couldn't count the times the a2 rear sight getting misused zeroing and failing to qualify. (NCO's directing troops wrong "many times" to adjust elevation knob ) I got in to many pissing matches over that. Then having this happen, sight getting moved after zeroing due to rubbing up against something or during cleaning... Most Units don't let troops"paint or mark on them" I don't ever remember taking time to dial in for elevation when I carried a a2 heck I never adjusted sights with M60 I'd adjust off impact of rounds. Range estimation was something I and many other practiced when I was A.D.
Now as a civ different story. Practice trying to make small hole with bunch of bullets or KD range... Rock on.