OrCAD: Determining which trace in Secondary Sweep is which after simulating
When you view the waveforms, you can right click on the trace, and click "Trace Information". This will show the parameter value used corresponding to that trace.

EDIT

Double sweeps:

To be honest im not sure how to read the sweep value then, but if you use "parametric sweep" instead, you can do as i described above. So you use "primary" and "parametric" sweep.