The best way to deal with extremely large gaps is to keep your hand as small as possible. I know it sounds crazy, but if you only open the gap needed to cover the stretch (in this case 1-2) and keep the rest of the hand small, closing the gap as soon as you can, it'll be easier to play. By keeping the hand in a comfortable position, you are reducing tension, which is the point of this etude (more or less).
Also, Chopin was said to have told students that this etude was meant to teach them to play widely arpeggiated passages like bow strokes, so think of the bow when you play. (I don't know how much you know about string technique, but the gist of what you'd need to know for that is to keep the arm flexible and moving steadily, for any sudden, jerky motions will make ugly sounds.)
Hope this helps!