I suspect you're right in assuming that many people have not taken this into account, at all, certainly it wouldn't have automatically jumped into my head (though I'm sure some nighttime practice would have led me to the same experiment).
The primary factors, by the way, are barrel length and gas volume. However, without experimenting with different ammunition you cannot find one and the other is fixed by the weapon chosen (and may be a compromise anyway, if it's for concealed carry, for example).
So-called "Plus P" rounds will always have more flash, basically, since they use more propellant, thus more gas and push that along with the lighter round out of the barrel more quickly.
I'm not at all convinced (putting it mildly) by "high velocity" handgun rounds, such as "Plus P" anyway, though this is not the topic for that. However, it's interesting to note that avoiding them in low light will reduce the likelihood of being dazzled by your own muzzle gases.
If you conduct any more experiments, do please let us know.