I always let my grain sit in the sparge water for 15 minutes, but the actual lautering only takes about 4-5 minutes on top of that. I'd say the total time I spend batch sparging takes about 20 minutes.
Then, while waiting for the boil to start, I can usually collect 2-3 quarts of wort, which I will use for starters.
You're not gaining anything by letting it sit. I've experimented with letting it sit up to 20 min. down to running off immediately (like I do now) and found no difference.