K I'm changin what I said earlier, rigaudon is probly DipABRSM [the most difficult spot is only a couple of measures], and the piece itself isnt' overly long. The first movement of Sonatine is probably around the same, maybe a little more difficult because of the extremely awkward hand crossing which comes up all over the place. Also, being able to do that with such a light touch requires a pertty good technique. The 2nd movement of Sonatine is probably easier than the rigaudon once you have the notes down. It's not the easiest thing in the world to sight read because there are some awkward chords. I'd say the 3rd movement is more difficult though, because it has the same dificulty throughout. Hands crossing over, repeated notes, this takes crazy accuracy and dexterity at the very end while also maintaining the same light feel as the first movment [in most parts]. So it'd be like this:
2nd mvmt
Rigaudon
1st mvmt
3rd mvmt