I just put the page in the middle of the scanner glass and scan it in. I rotate the scans in photoshop. I do a lot of scanning and they're of varying paper sizes, so I cannot paste guidelines on my scanner.

A lot of scanners cut off the scans at the side so you'll have to find a way around it.

chiyo_sama is a very good redrawer so you don't have to worry really XD But don't you already have a lot of things to do...?