GX200 My Settings for street photography and flash settings

Hi,

I have had the Gx200 for a little while now and I am just trying to get used to the settings,

I am keen on street photography and wondered if someone could share ideas with me on what I could set the My Settings to for this purpose.
What I think I need are –

ISO 64 -400, Shutter speed at around 1/125th sec, F 4.6, centre weighted metering, set to snap focus and 24mm.
Does this sound ok?

My other question is that I will be using it this weekend at a nightclub environment and will be needing to take shots of friends etc.
I will be using the flash but I don’t really know what flash settings to use.

I was thinking I need around 1/125-1/160 on the shutter and the widest aperture with the lowest ISO I can manage with those speeds….but what about flash, do I need to tweak those settings?
All of my pics will be black and white if that helps?
Cheers,
Al