STL Export File Size via API

When saving a part as an STL there is a checkbox in the options dialog to preview the resulting file, both in triangle count and file size. Is there a way to access those values through the API? I can get/set other values in that dialogue (e.g. swSTLDeviation, swSTLAngleTolerance), but I can't find any documentation of where to access that file size.

For context, I'd like to know the file size in advance so I can tweak the Deviation and/or Angle Tolerance to maintain the highest resolution possible while limiting the resulting file size so the slicer doesn't choke.