Call ducks are definitely usually 26 days, so whoever told you 28 or 29 days was misinformed. 29 days is too long even for standard large fowl ducks.
Yes I did see that in the eggs. I just sent for more from NY. I hope they are fertile at this time of year.
Draw down is when the air cell starts to pull down one side of the egg as the duckling inside begins to position for hatching.
Call ducks, because of their short necks and beaks, can have a hard time hatching on their own, especially if they are from show lines. They very often need help to hatch, or they die.