It depends on many different factors; In the circumstances you describe, they can make from one to a dozen or more (many of those could be less than optimal). I would watch to see how many they start, then cut out (destroy) those that appear too small, or that are too far from the main cluster (they could be chilled). Leave at least the two best looking cells.
When you give them the eggs and capped brood, be sure to include attached bees but be sure not to include a queen. Keep an eye to ensure that enough bees stay with the brood so it doesn't become chilled (and die).