Hi, I'm new around here, also with a Mossberg. But that's not what I wanna talk about.
Lights. I know, I know, it's tacticool to put a light on your gun. And it's awesome. But, there's an easier and better way, in my opinion.
Head mounted lamps. Keep one by your bed, in a drawer, etc. Get up in the night to go to the bathroom, grab the headlamp and put it on. Develop familiarity with it.
Why do I like the headlamp over the shotgun light? Well, it's mounted to my head and it lights up the direction I am looking in. I can look over my shoulder behind me and have light, or look to my right or left and have light. I don't flag(point a gun barrel at) anyone I don't want to shoot with the light. It doesn't add extra weight to my shotgun's front end and doesn't require any tactical rail mounts.
Other advantages: with the light mounted on your face, you can illuminate your action and ammunition.
Basically, forget the damned tacLight, and get a head lamp. They are so much better. Also, if the power just goes out, having a headlamp hanging from the bedpost is useful, while carrying around a mossy with a light on it is too much. You maintain light even if you need to put your gun down.