Do not apply in the R3 since you will be wasting your time. Even the admission officers at various schools (Wharton & Tuck) told me that the chances are significantly smaller. Using their own words ... "There is a chance to be admitted in R3; however, we highly recommend that you apply in R1 or R2." Good luck!
Forgot to mention that another issue that you will face when applying in R3 is that if you do not receive an offer from any of the schools that you applied, it will be extremely hard to write the essays as a re-applicant considering that your candidacy will not have improved much in 6 months. (R3 deadlines are in March 2010 and the R1 deadlines for the next year will be in October 2010 ... 6 month gap).