I'm on DJ347 in a couple of weeks, using 2 complimentary upgrades. In EF I can see the below availability:
View attachment 5782
Business fare buckets listed as being available are J6 / I7 / D7 / C7, so some of those numbers actually exceed the number of J seats available (as I have 2 out of the 8 seats booked, so theoretically there should only be 6 seats max left, as J indicates). I'm not convinced that DJ use these as Business fare buckets though (Even though that's what EF say they are) - there are some other flights I've looked where J availability is 0, but C/D/I still have 4-7 seats available. Additionally, when I look for Fares on DJ, on a random selection of dates, only two fares for J ever show up, and none for I, D or C, even though those fare buckets are available on the flight. Just wondering if any of these buckets are potentially used for the Award seats and/or complimentary upgrades? Or maybe I'm reading into it too much...
View attachment 5781
Interestingly, it also shows P7 (First) in the availability - assuming this might be for codeshares with airlines that have F (Delta, Etihad, Singapore etc)?
Business rewards have booked into H.
C D I book into Economy from my experience and others on other threads.