I generally avoid using S-log at night since there will be a lot of color noise, etc. S-log is meant to be used in high contrast environments so that you can use the camera’s dynamic range to capture all of that information. At night, even when passing through lights, etc., your scene won’t really warrant using S-log.
If anything, I would use Cine1 since it has the least noise but still has good dynamic range. Use Color mode: S-Gamut Cine if you want to grade in post, but overexpose by a third to one-and-one-thirds of a stop and bring your midtones down in post (it’ll be noisy if you do the opposite and try to brighten your scene in post). You could also use Color mode: cinema if you want it good out of camera. I haven’t used HLG since I use an A7Sii but I’ve heard that’s a good option for night time filming as well.
If you’re adamant about using S-Log at night, I’d recommend using a conversion lut on a camera monitor so you have an idea of what the footage will look like once it’s converted to rec.709