I use this one at the range - it has explanations at the bottom for what one is likely doing wrong
TROUBLE SHOOTER XL | Diagnostic Target
for example
Can't recall if I asked this before or not but do most of you experienced shooters shoot with both eyes open? If so, how long did it take you to develop the quick focus on the front post.
Depends on the platform and range.
On rifles with RDS, I have been shooting both eyes open, especially at reduced ranges (under 100 yards). For distance and precision, I go left eye closed.
Pistols are much the same. Point shooting at ranges under 15 yards for the first two shots and one eye closed for the head shot generally in the Mozambique. Again, precision shots and distance means one eye closed.
Point shooting can be valuable in close environments, but is rarely taught anymore. Flash sight is the more common approach to shooting that most schools employ.
As for how fast you pick up the front sight? Time and practice. Can't quantify it with a number, it just comes around eventually.
I've tried off and on and if I concentrate I can allow my dominant eye to make out the sight but it's not a natural acquisition. As a result, 95% of the time I go with one eye.
To complicate things I'm have presbyopia so at the range I have a set of glasses with a 1.5x lens for my shooting eye and normal for my non shooting so I can focus on the target (between shots) and on the sights (during shots). Getting old sucks.
I need to practice without the mag lens though since in defensive situations I won't have my magic glasses. Problem is, the front post is blurry and forget about the back sights.