Not the kind of tip you were hoping for, but get a different recording. Previn always screws up with Rachmaninoff or Tchaikovsky- actually he pretty much screws up everything, he's my all-time least favorite conductor. His stylistic eccentricities are just unacceptable. My personal recommendation for this piece is Raphael Orozco, with Edo de Waart the the RPO (a NAXOS label, all five Rach concerti in one box!).