I, too, use DxO. I use the copy files method. I don't bother copying the dop files back, I just keep the keepers folder. Perhaps I delete the non-keepers.
I'm working on a slightly more complicated flow. My problem is that my concert photos may suffer from harsh lighting and I can't picture in my mind what the photo will look like after processing. So, I do a batch edit in DxO of all photos, dumping them into maybe TIFF or jpeg. Then I sort through them in PM. I'll need a script to then back-annotate the star ratings to the originals, and I continue the editing. It's a work in progress.
I had completely dumped Lightroom, even before DxO. I did everything in Bridge/Adobe Camera Raw/Photoshop. Now I'm trying to integrate both DxO and PM. Still trying to work it all out.