Cute block!! I would just remake your four flying geese.if you have fabric. I looked at the directions - and that method would not be my choice for making flying geese - too much chance for error imho. I would do it by using the rectangle and squares method where you place a square on top of the rectangle at one end and sew on the diagonal, trim and iron - then repeat with the other end. The measurements are below for the two different sizes.
For the 16" block, I would cut 4 black rectangles 4.5 x 2.5 and 8 white 2.5" squares (finishes 4x2)
Ffor the 12" block, I would cut 4 black rectangles 3.5 x 2 and 8 white 2" squares (finishes 3x1.5)