For AF, you can search for award travel availability (O for business and X for coach I think) using ExpertFlyer or one of the free search tools such as this fare class site. It's been pretty consistent for me. However, once you find availability for the routes/dates you want, good luck having those options show up on delta.com. You might get lucky or, more likely, you'll have to call Delta and tell them the flights you're interested in.