Personally I'd just go the old-fashioned route and make a character set, but to each his own~
I'd love to do that but the problem is, it's going to be affected by the map's screen tint.
You can always set the character's blending to "Add". That would help compensate somewhat for a dark tint.
I tried, but it's not working with Add-Mode either. sadly. (You'd see if you tried it yourself, it just doesn't really look like light is spreading at all )
Maybe it's just the graphic you're using?
It's a bright, yellow light and unfortunately, the dark blue tint takes away all of the color
Separate names with a comma.