In researching homemade ricotta, I consulted Smitten Kitchen, Serious Eats, Sweet Paul Magazine, and Not Without Salt.
This will yield about 1 cup of ricotta, much more than you’d need for 4-6 tartines. Double the tartine recipe if you’d like, or reserve the ricotta for other purposes — like ricotta pancakes!
I let the cheese drain for two hours and it was still quite soft; if you want a firmer cheese in less time, you can fold another cheesecloth or a few paper towels and place it gently over the cheese, then place a weight over it (canned foods, for instance) to press out additional moisture.
Also, as noted above, I substituted 2 tbsp of the vinegar for a Japanese seasoned rice vinegar (with 1 tbsp white vinegar) and thought the resulting taste was just barely noticeable, in a great, subtly savory way.
Finally, if you tend to have 2% or low-fat milk in the house, as I do, just increase the cream to 1 1/2 cups and decrease the milk to 2 1/2.