I steep grains for an extract brew for about 20 to 30 minutes at around 150°F to 160°F in 2.5 gallons. My well water has a pH of 7.4. A pH over 6.0 can extract some tannins from the grain. I do this just as a safety factor even though the the amount of grains is small and the short time in the water at high temperature may not extract any noticeable amount of tannin.
I rinse the grains with a quart of water after the steep time is over. This will get some extra color and flavor from the grains.
For most of my dark beers I add all the extract at the beginning of the boil. Doing this with the CS recipe seems to bring out more complex flavors in the finished beer.
I'm getting my brew snacks ready during the steep time. No risk of a boil over during this time with the heat off.