As I have said many times, it is very difficult (if not impossible) to describe movements in writing so that they can be safely be imitated by a reader who has never seen the movement before. As I reread this old post of mine, I still think it is a good description. But will someone reading it be able to reproduce the movement I am trying to describe without a demonstration? Most likely not.
The idea of breaking the thirds in lines and working on them separately is a very good one (pianohopper – although I don’t see any triplets in the right hand…) If you do so you must of course preserve the original fingering, for when you join the notes to make up the thirds.
Allchopin is absolutely right as well: consistent practice will work wonders. The only proviso is that you aim your practise at effortlesness. If you have the wrong movements, consistent practice will not make that much of a difference in how labored your playing is. However, you will know you are on the right path if as you practise, it becomes easier and easier (which seems to be allchopin's experience).
Usually our unconscious – given the chance – can find out by itself the best movements if you investigate enough. The worst one can do is get a fixed idea of what the movement is and stick to it no matter what. Try different things and go for the ones that feel the easiest. You must do that on very small, representative sections so that you can do it at the final speed (So Ted’s – Brendan’s suggestion of “microsleeps” is also good) in a very short time – the movement at speed must be figured out, since at slow speeds you will get away with inappropriate movements.
Once you figure out the movements, do repeated note groups, which is a very good strategy for this study – but brace yourself: you will have to work in very small sections (7-10 thirds at a time) and it will look like it will take forever to master the full study. Fortunately there is a lot of repetition, so make sure you analyse (in the sense of identifying repeats) the study first to decrease your workload.
Finally, the movement you will end up using (which is to a certain extent personal) will also depend on the fingering you use. I strongly suggest you use Chopin;s original fingering, but if you look up Cortot’s “Edition de Travail”, he provides 10 different fingering possibilities (Chopin’s included) for you to investigate. He also has many interesting preparatory exercises for this study.
Best wishes,
Bernhard.