PA constant efficiency contours

Hi,

I am trying to do a load-pull simulation to study the optimal load condition for a CMOS Power Amplifier. For this, I use the parametric PSS simulation with a portAdapter to traverse all possible reflection coefficients (gamma) on the smith chart. After the simulation, I use the 'Power Contours' option in the Direct-Plot form to plot the contours of all the values of gamma which result in the same output power.

Is there any way I can set up the simulation to plot constant efficiency contours or in other words contours of gamma which result in the same drain-efficiency.

Thank!