Yes I have the DWX OR and have mounted a Impact Machine plate cut for a DPP as I am using a Vortex ST optic. It's the plate that doesn't have an extension for BUIS. This is a range gun so no need for irons.
Prior to mounting the plate, I ordered 6-40 x 3/8" long flat head screws from McMaster-Carr.
Once I received them I took a measurement of the depth of cut in the slide where the screws are inserted. I then filed the screws to fit (made sure they didn't "bottom out") cleaned the slide threads and screw threads w/acetone, added a bit of Loc-Tite #242 to the screws and installed the plate with 20 in/lbs torque. I then cleaned/LocTited the optic screws and plate threads, mounted the optic and torqued those screws to 20 in/lbs as well.
Now have about 1100 rounds thru the gun and no issues.
My view is the plate screws that are provided are much too short. If I was going to shoot w/irons I would replace cover plate screws as well.
Just sayin', YMMV