The easiest way to export data to an individual worksheet is to name the data range and make sure there is nothing below the range. Save the workbook and define a Monarch project using the report and model with a project export. Make sure you specify in the project export that if file exists, add data, and if table exists overwrite data. Then use the following command line:
Monarch /prj:"project file" /px:"job name"
The switch for all exports in a project, is /pxall
If you do not want to use projects, then you need to specify some or all of the following:
/set:"field name"="field value"
/R,S,T (Report, Summary or Table window.)
Hope this helps!