Indigo, I can't really answer that. But here's some thoughts, and I'm not an airbus pilot.
If Airbus publishes a "landing climb" figure, (all engine speed for landing flap go around) that may be the minimum drag speed in that landing configuration. V Ref - 5 as a guesstimate?
Approach climb speed may be min drag for approach configuration, depending on how airbus certifies there airplanes.
"improved climb" if that's an airbus term, may give you min drag for that flaps/slat takeoff configuration.
If you find some hard data, please post.