The alpha channel of the normal map is already pure black. I don't have a glow map, and I've never been able to get them to work, there must be a setting in the nif to make it use one? Would I make it pure black to make the texture look bright but not glow or have HDR?
Like I wrote above, a glow map is a mask that is applied to the emissive color. Without glow map the whole mesh will be affected by the emissive color. If you want less glow simply adjust the emissive color. Can be anything from solid black to pure white - in your case something inbetween would work best, like red, green and blue @ 0.5 for example. You can even use a color if you want, like yellow or red or whatever. But in most cases the texture should be enough for adding color.
A glow map is only necessary if you want certain parts to glow and others not. Or if you want certain parts to glow stronger than others. Can be seen on the Daedric equipment for example - the red parts glow, but the rest of the mesh doesn't. Since splitting up the mesh into red parts and other parts is not an option (the red parts are only part of the texture and not part of the geometry after all) a glow map is needed.