Use nylock stopnuts probably M5s and be happy.
I never saw CW threaded motors until last year and have been building copters since 2013. I prefer all CCW and purposely purchase that as it makes maintenance simpler and cheaper in the long run.
EDIT:
If you choose to use prop nuts that aren't nylock stop nuts, carry a small nail and tighten the nuts before
every flight. If you screw it up, you get to hear this unique little pop just before the copter tumbles from the sky.
Good luck ever finding the prop or the nut. :black_eyed:
And welcome to the FT forums.