Dark stock proportions
According to the Culinary Institute of America their basic formula for all Meat or Poutlry based stock would be:

8 lb/3.63 kg bones and trimmings
5 -6 qt/4.80 - 5.76 L water
1 lb/ 454 g Standard or White Mirepoix

You would not need any actual cut of meat for a stock according to them.  Those would be reserved for making a broth.  Their basic formula for broth doesn't specify a ratio between meat and bones just 10 lb. of meat or poultry including bones to 5 qt water.  If you are converting a stock into a broth they give the formula of 3 lbs meat to 5 qt stock.  Based on that a good starting point might be 7 lb bones and 3 lb meat to 5 qt water.

Just an FYI they make all their mother sauces using stocks, broth seem to be reserved for soups and other applications.