You could "draw" the auditing marks on the spreadsheet.
Make sure to set the transparency to 100%.

You can set that by right clicking on the drawing and
select "format autoshape", "colors and lines", "fill".

You can then set that as the default by right clicking on
the drawing and left clicking on "Set Autoshape Defaults",
then the rest should look the same for that workbook.

Good Luck!