Regarding the Eleanor Burns method, there is a simple formula for getting the finished FG you want. All FG units are twice as long as they are tall. So a four inch goose is two inches tall.
Figure out the size of goose you want, add 1.5" to the long measurement and that is the size of the smaller square. so a four inch goose would have a 5.5" small square. Now add another 1.5" to that and that is the size of your big square, IE 7". Now proceed as she recommends to make your geese, you can then square it up with any square ruler. You need a 1/4" seam allowance at the top and none at the sides, even off the bottom. Make any size you want. The special goose rulers are nice but not neccessary.