Ok, I havn't really studied scarbo but I no what your finding hard.
Your looking towards the wrists to do the work, Don't. Totally relax the wrists, use the arm. Relax the whole are from the shoulder. Let the arm do all the work, do not try to relax the wrist, it will come naturally if the arm is relaxed. If you play it with just your fingers it will go wrong. Let the arm do all the work.
Pure relaxation is the key to all difficult passages. If you try to play fast you'll tense. Find the positions, practice it in positions, look at the arm movement during everything, overdo it slowly, and get a feel for the shapes it all creates, (Circular, triangular etc...) and then use he arm to create the shapes, and just let the fingers mould into the keyboard and press the note, the arm will provide the power, the wrist will get you the staccato.
Hope that makes sense!
