12 moa dot would be a blob obscuring all in the viewfinder.12 MOA would be perfect,
they do now combination of the 2 moa dot and 30 moa circle. it they would make it a 15moa circle/crosshair - it would be what you want.
2moa dot as an option is perfect as it is what you want to shoot at the bullseye center at 25yds target. 1moa is better but too damn small. 2 moa is good, and if you put brightness to max on most models it grows into almost 5moa anyway.