It automatically listed me as "CPU eligible" from the start. When I called a few day later, the agent said, after confiring with a supervisor, they could also wait list me for J award space which now shows up separately.

edit to add: This could be one of those cases where UA threw me a bone. My original itinerary had me in F under IN but I asked for a new itinerary due to a very large schedule change. The new flights didn't have IN available on either flight but they opened it for me on the TATL section. So maybe they somehow tagged on "CPU eligible" for the domestic flight (followed by my request for IN waitlist days later).