If your saddlestitched document is thick, make sure you allow enough margin between the holes and the spine of the document if you plan to drill holes. Saddlestitched pages are nested, so if you don’t allow enough margin, the holes on the pages near the middle of the document will drill too close to the fold. If you are uncertain about whether you’ll have trouble drilling, ask for a dummy, saddlestitched and drilled, before you print!