Check out ffxiclopedia's forums, specifically the choco raising/racing forum (under the crafting section). Loads of info there.
The training plans are approximated to be somewhere between the effectiveness of an adolescent+ care plan (Carry Packages, Exhibit to the Public; takes about 5 successes to get a full stat rank) and an adult care plan (Messages, Treasure, Play; takes about 3 successes to get a full stat rank).
It's also important to note that unlike the care plans, there is no day wait required for racing training, *and* the racing training doesn't decrease opposing stats the way care plans do. So it's a good way of getting a racing chocobo that actually has high enough Discernment to learn abilities, or a digging chocobo that has high enough Endurance to last a while.