Adjust page margins

Question

The below code generates a two-page document with a 1" margin around both pages. Need to adjust it to around 0.5". I've tried a few workarounds, but none seemed to work.

I've tried to implement the workaround mentioned on PDF margins - Google Script but failed.

function generatepdf() {
  reset_rows();
  hideprow();
  importdata_summary();

  var sourceSpreadsheet12 = SpreadsheetApp.getActive();
  var destSheet6 = sourceSpreadsheet12.getSheetByName("Request_Info");
  var specsheet = destSheet6.getRange('C2:C2').getValue();
  var companyname = destSheet6.getRange('C5:C5').getValue();
  var ref1 = destSheet6.getRange('G4:G4').getValue();
  var pdfName = specsheet + "_" +  companyname + "_" + ref1 + ".pdf" ;

  showSheet(specsheet);
  showSheet("Quotation");
  hideSheet("Request_Info");
  hideSheet("Summary");

  var sourceSpreadsheet = SpreadsheetApp.getActive();
  
  // Get active sheet.
  var sheets = sourceSpreadsheet.getSheets();

  var sourceSheet10 = sourceSpreadsheet.getSheetByName('Request_Info');


  // Get folder containing spreadsheet to save pdf in.
  var parents = DriveApp.getFileById(sourceSpreadsheet.getId()).getParents();
  if (parents.hasNext()) {
    var folder = parents.next();
  }
  else {
    folder = DriveApp.getRootFolder();
  }
  
  // Copy whole spreadsheet.
  var destSpreadsheet = SpreadsheetApp.open(DriveApp.getFileById(sourceSpreadsheet.getId()).makeCopy("tmp_convert_to_pdf", folder))

  var destSheet = destSpreadsheet.getSheets()[0];


  // Replace cell values with text (to avoid broken references).
  var sourceRange = sourceSheet10.getRange(1,1,sourceSheet10.getMaxRows(),sourceSheet10.getMaxColumns());
  var sourcevalues = sourceRange.getValues();
  
  var destRange = destSheet.getRange(1, 1, destSheet.getMaxRows(), destSheet.getMaxColumns());
  destRange.setValues(sourcevalues);

  // Save to pdf.
  var theBlob = destSpreadsheet.getBlob().getAs('application/pdf').setName(pdfName);
  
  var newFile = folder.createFile(theBlob);

  // Delete the temporary sheet.
  DriveApp.getFileById(destSpreadsheet.getId()).setTrashed(true);
  
  //cleardata

  var sourceSheet3 = sourceSpreadsheet.getSheetByName('Quotation');
  sourceSheet3.getRange('J6').setValue(sourceSheet3.getRange('J6').getValue() + 1);

  showSheet("Request_Info");
  var sourceSheet5 = sourceSpreadsheet.getSheetByName('Request_Info');

  showSheet("Request_Info");

  hideSheet(specsheet);
  hideSheet("Quotation");
  showSheet("Summary");
  //reset_rows();
}