Sorry for the late response.
My slideout is 80 3/4” tip to tip, and the fabric on the awning is 81 1/4”. While this works great for keeping debris from jamming up, there are some things to watch out for.
1. Birds like to nest under it in the spring (assuming the slide is out for a bit), so you’ll still need to do a visual inspection before closing up. It doesn’t take long for them to get enough stuff up there to be a problem.
2. It tends to flap in windy conditions (>25mph). At Kitty Hawk, I had to throw a ratchet strap over it to calm it down. Shakes the whole trailer with a deep vibration.
Both are only slightly a problem when compared to having to crawl up there and clean out a jam.