Potatoes do cook down, consistently about 100 gram per lb. The size of your potatoes will determine the weight, so generally we measure the serving size by the gram rather than the number of potatoes. But if you prefer to count, there are about 3 – 5 whole baby potatoes per serving.
If you do not want to turn on the oven, place potatoes in a foil pan, covered, on a grill. Pay attention to the temperature; and the potatoes will most likely cook in less time.