Bartok: No. 6 from Dances in Bulgarian Rhythm (Help with repeated notes!)

[kelly_kelly]

I assumed the opening ostinato (and every similar figuration) would best be played 5-1-2-5-1-2-5-1 and so on, but while watching some performances I found that everyone seems to play it 5-1-1-5-1-1-5-1! I just tried it and I find it much more difficult to play evenly. Is using the second finger acceptable, or am I somehow missing the point? Also, any pointers for repeated notes in general? I have about 2.5 months to learn this piece and I just realized my repeated note technique is somewhat lacking...