Thanks to everyone for their input.
Eric - your suggestion of chgobjaud seems to be the best option.
Something like the following for all the jobds I'm interested should do the
trick as it should tell me everywhere it's used, but it may take some time
for all the functions to hit it since some jobs may run only at year end or
even on demand only.
CHGOBJAUD OBJ(TCJOBD) OBJTYPE(*JOBD) ASPDEV(*) OBJAUD(*ALL)
(And your second option, (the worst way) - is definitely effective but
would probably result in a bit more work than I need at the moment ;)