I always shoot manually at night with my gain at +6, with the iris wide open and use the shutter wheel to adjust to different lighting. Of coarse keep your filters set to off. Those are only for daytime use. Using the night preset is going to end up turning your image grainy. You can program the presets, but that's a little complicated. As far as getting rid of the bass over modulation. The on-board mic isn't suited for loud music. Even when I've used my shotgun mic, it sounded bad. What you may want to do to capture audience sound is use a mic suited for loud noises. I've even used a wireless mic for this. I've been very disappointed while shooting live shows, because your levels appear to be fine, but when you get home, it's all muddy and not usable. Invest in a wireless mic and get an attachment to plug into the mixing board and you will get a great sound.
I have actually start to adjust and customize the presets, and have noticed a very little difference, could you point in the direction of one that helps in low light? and I mean, extremely low light, like a club.
There are no presets available. The best thing to do is open your iris all the way. Boost your gain as far as it will go, without it becoming too grainy. Like I said I use +6, but you can try going a little higher if you want. Use your shutter control for adjusting to changing light situations. The custom settings are mainly used for picture adjustments and not for light control. When you go to edit, you can use color curves to further boost light levels and balance out things a bit. Make sure you stay steady on a tripod if you are shooting low light scenes and/or move slowly, unless you like tracers and trippy effects. I would also rig up a light to use on your camera. Something that is not too bright. Just enough to light up faces that are close to you. Maybe something with a dimmer for adjusting to certain scenes. Hope this helps a bit.