Ahh! That's brilliant. I'm just having trouble getting the line of sight to detect which index the tileset is on.
You could always do it with just tiles or sprites, you would have about 3 layers of the map, one for the darkest tiles, one for the mid-light ones, and a third for the ones that are completely in the light, and then have multiple circles that are different sizes from each other and with the blend modes have them reveal each layer of the tilemap.
I have been meaning to try this method for a while now but haven't got around to do it, if you try it and it works please do tell!