Hi there,
Let’s simplify, and move most everything into the shader!
On the far left of the material window, you can see two variables. Column and row. It should be pretty self explanatory, but you simply put in a 0 in column to keep it in the left column, and then pick a row by number. In this image, you can see I have column zero, row 1 (this is 0 based, you could always fix it to start at 1). There is also a parameter for brightness, and color as well. This should help you simplify things greatly!
Here is the texture I used. Notice I put the “glow mask” in the red channel, and kept the circles themselves in the green channel. This saves us texture memory by packing the information into one texture.
I hope this helps!