This post is just for posterity.  I'm updating my Pythia8 jet-finder code to simulate the TPC response as determined in the Run 9 dijet embedding.  Rather than figure out the functional form of our calculated tracking efficiency, we just opted to use the histogram.  The plots below show that all checks out: the jet-finder reproduces the efficiency.  Considering the significant error bars out at really high pT (~8 GeV/c), it might be wise to use larger bins or just a constant fit out there...