Frank: If you feel really bold, you could rewrite Winsteps.ini in your batch file.
Append the column selection line that you want each time.
1) Find the path to Winsteps.ini on your computer disk
For me it is:
"C:\Documents and Settings\Mike\Local Settings\Application Data\Winsteps.com\Winsteps\Winsteps.ini"
2) Launch Winsteps, analyze a data file,
3) Output Files menu: make the PFILE- field selection. Click on Make default
4) Open Winsteps.ini in NotePad. Copy out the OFSFIELDS=line
5) In your batch file, add this line before calling Winsteps in order to append the Field selection to the end of Winsteps.ini (overriding other field selections in Winsteps.ini)
echo OFSFIELDS=NYYYYYYNYYYNYYYYYYYYNYYYYNYNNN >> "path to Winsteps.ini"
6) back to 3) for the next field selection