I use a Quikrstuff Mach 2 for my Delite. It works fine with the rear fender. The cross bit thingy can be adjusted to tuck up a bit underneath it and it's totally secure. For extra-safe backup, get one or two of the locks they sell with it (they go through the wheels and the bars).
Looks like they have a 6-week backlog on orders, but it's less than I waited for mine. The thing is so easy to put on and take off, no tools needed, and it folds up easy to store in the box it came in. I love it and it was worth the wait (and the price).
View attachment 154817