I use a dab of DayGlo-Orange paint on my sights, and it stands out surprisingly well in low light conditions (dim parking lots, rooms, walkways). No, they don't "glow," but I haven't run into a condition where it was so dim I couldn't see the sights yet still see a target. I prefer orange as little in nature is orange and BGs don't favor colors that stand out.
Another possible choice is one of the various colors of bright nail polishes found at the drug store. They stand out best when applied over a white basecoat.
At $4-$5 a bottle, it's worth a try.
The problem with the "glow-in-the-dark" sight paints is they must be "charged up" to be most effective. That's not going to happen when you've had it in your holster under clothing for a while.