How small can you make a barcode in Word?

I wanted to see just how small I could make a readable printed barcode in Word so I wrote a VBA macro to generate barcodes at different sizes to test it out.

Sub insertbarcodefield(ByVal barcodetext As String)
  Selection.Collapse Direction:=wdCollapseStart
  Set myField = ActiveDocument.Fields.Add(Range:=Selection.Range, Type:=wdFieldEmpty, text:=barcodetext)
End Sub

Sub makebarcodetextsize(ByVal text As String, ByVal barcodetype As String, ByVal size As Integer)
  insertbarcodefield "DISPLAYBARCODE """ + text + """ " + barcodetype + " \t \h " + Str(size) + ""
End Sub

Sub dobarcodes()
   barcodestring = InputBox$("Barcode String")
  For i = 400 To 1500 Step 100
     makebarcodetextsize ltrim(Str(i)), "code128", i
     Selection.TypeParagraph
     makebarcodetextsize "a" + barcodestring + "a", "nw7", i
     Selection.TypeParagraph
  Next
End Sub