Hi,
here´s one I found quite simple and useful.
Open the .txt File with a editor and configure the analyzer parameters after your fashion (basically its just commenting/uncommenting lines and setting a fixed parameter)
You can choose either THD over Frequency at a fixed Amplitude, or THD over Amplitude at a fixed Frequency.
The analyzer runs multiple transient runs, which means that calculation time becomes long and raw-File size can become very large.
Plotting results: View --> Spice error Log and then Plot .step'ed .meas data
regards
Calvin