After 6 months and 6k miles of commuting, I would also recommend the Coretec Sport wedge bag. It is easy to remove or place on the bike, and the handle makes it easy to carry into the office. The expandable sides are nice when you need them, although I can fit a laptop and planner without exanding the sides.
I shortened the bungees for the first install, and haven't noticed any stretching. I fit the rear clips under the back of the grab bars, and the front to the holes by the rear pegs. I have seen no scratches on the grab bar with this method, although I am still careful pulling the bungee over the side panels. The rubber pad on the bottom has never slipped, and the rain cover does works well, as tested several times this month.
I hope this helps- good luck. I also hope to finally get some time off of work, and try using this on some overnight trips.
Be safe!