BTW, the only filtering I used in the optical train, were an LP filter, used to help reduce light wavelengths such as mercury vapor lights, which will destroy extreme low light astronomical images.
This might be a dumb question, but is your equipment stand alone? Or are you tethered to a power source and stuck in your backyard?
And is the filtering for direct filtering? Like to stop the light from the streetlight on the corner? Or just light pollution in general?