I think you really just want it as cold as you will be serving it. I typically did it for a couple days.
There are a couple advantages besides clearing. The trub and yeast cake also compacts really nicely which is nice when syphoning. Also the cold beer will absorb the CO2 easier so you can force carb it down around 8-12 PSI instead of 25-28 psi.
I once read about the dangers of drinking, I have since stopped reading. - Unknown