Well, that depends on what you are recording.
24bit and 48khz is a god starting point. Keep gain well below clipping in the context of what you are recording.
I normally enable the limiters as they do more good than harm IMO.
If I set the gain correctly, then they will never engage. If I underestimated the sound levels, I find the limiter less offensive than the clipped sound. Win win.
You can enable a safety track if you feel unsure about setting the gain correctly.
I don't think the build in mics are good for very loud music.