...

1. Move the bottom tape towards the mouth to allow for the full seam allowance.
2. Single exterior rectangle.
3. Make wider (and thus shorter)
4. Add loops through closures
5. Remove line holding flap. Replace with rubber bands
6. Add grommet in bottom for bridal to pass through

New Dimensions:

Rectangle:

• Height = 14.7395"       V/[pi*((ID-2*clearance)/2)^2] - tolerance

• Width = 17.1891"

Same dimensions for flaps and bottom.

Sources

Dimensions for main rectangle: