You’re getting a lot of noise because you’re underexposing. Are you shooting in low light because you have no choice, or because you want a dark look? It doesn’t necessarily have to be dark to get a dark look. Professionals (and advanced ams) use a lot of light, and then control the look through setting their exposure and post processing. Do you have PP software that can do more than stitch?
As for the settings, I would start at 24 fps, 1/50 shutter (keep it at 2X the fps for now), open the aperture all the way, and then creep up the ISO to get proper exposure (and/or add light). Better to add light and reduce in post if you’re trying to reduce noise. Though technically, if you’re trying film noir, a bit of grain is kind of expected.
