This is mine.
It is based on a Mack stack pack. As you can see the lazy jacks run through grommets near the top of the side pieces. This helps stop things flapping even when the lazy jacks are slackened off and led forward. The zip on the top has a continuous line which means it can be undone standing at the mast and helps when it needs to be zipped up. The sides are attached to the mast with two turnbuckles and a hook per side.
I am happy with it and if it wears out will get it copied without change. I have thought about battens but see no real advantage.