The reason behind a more concentrated specialty grain steep is to reduce the chance of tannin extraction by keeping the pH lower. Keeping the temp below 170° is key. Between 150°-160° is a good range. It isn't necessary to hold a constant temp as long as it is kept below 170°. Temps above 170° can extract tannins.
My normal specialty grain to water ratio is 1 pound of grains to 1 gallon of water. Some people suggest less water than that. I normally steep for 30 minutes.
I was confused at first about "to 170°" but after I re read it I understand now. You steep for 20 mins or until the temp reaches 170°. That's why I pressed the 170° so much.