What is the original size of the excel file? I can't help you with your macro, but consider using an Acrobat preflight fixup to change the size of your pdf saved or exported (not printed*) from excel. You can duplicate an existing preflight profile from the little fly-out menu (Options), edit the settings and save the profile to a new name. You can use the profile in an Acrobat Action to quickly re-size your pdf. Tools> Print Production> Preflight> Fixups.
*print to pdf will probably result in an image file (not vector), producing a much larger pdf.