Post from Senormechanico and wife
We filled the bag 1/2 to 2/3 full.
Offshore cruisers might recognize the paper ! lol
Here's what my wife Janet said:
The beanbag chair we used on our boat was a child's size. It uses 6 panels along with a 8 1/2" circle at the top and a two piece circle with a 16" or 18" jacket type of zipper on the bottom. These numbers include a 1/2" seam allowance except the center line of the bottom circle. With the zipper installed the circle has a diameter of 20". I like to use a 1" seam allowance on the center line so the zipper has plenty of fabric under it.