This is where it all gets really mushy. There’s simply no way to put into words how you tell what is “enough” light and what is “too much” light.
A good general rule is that you need less light than you feel like you need, but that can only take you so far.
You really have to get out there and practice this stuff to develop the judgment necessary to figure out what is “too much” and what is “enough”.
There are ways to accomplish this that just about anyone can practice. One of the best things you can do is get a buddy to come to your house and set up about five targets in your house.
Have him go through the house and identify good hiding places for bad guys or other challenging areas in your house and then set up targets there. Use cardboard cutouts or spray-paint templates (there are many available) to put empty hands and hands holding weapons on the targets.
Only one or two of the targets should have weapons. Then go through and clear your house using an EMPTY WEAPON and your white light.
The goal here is to force you to examine familiar surroundings in a new light and to get you learning to use the white light minimally to navigate and to identify threats, it will get you using your white light techniques, and it may even get your heart rate and breathing up giving you a tiny taste of some of the stress that will be in play should you have to do it for real.
The goal should be to go through the house multiple times (with different target placements, of course) using less light than the previous run to find out how much light you truly need.
Professional training is, of course, better than this approach, but this approach is better than nothing… and nothing is what most people do for low light training.
12 shots with Welder’s goggles on (an actual LE night fire qualification in one of the states in our nation) is NOT low light training.
Shooting at night with patrol cars behind you lighting up the target isn’t low light training.
If you’re not at least trying to replicate the circumstances you’ll face should things really go sideways you are cheating yourself.
There are no shortcuts here. You have to be willing to put in the time and the effort to get these concepts down.