I just booked two tickets from BOS to DUB in June for 60k. The flights are on AF. I was even able to include a stopover in CDG for a week at no charge. The calendar search will not show partner awards as being available at the low level even if they are. If you search by schedule and an AF or KL flight shows up, then it will be at the low level. AF/KL flights will not show up at all on delta.com if the low bucket is not available; the flights will simply be omitted. It is a pain in the neck to go though and search day by day but it is doable, and AF/KL do have some decent availability for this summer… at least they did three weeks ago.
When calling Delta to check for partner availability I have had varied success. One time I had an agent who was great and told me about the delta.com trick to make the partner awards show up. Most of the time, though, the agent is clueless, and I can pull up partner awards that the people on the phone don’t even see.