This number of pages is the absolute maximum that we'd recommend wire stitching. You can see on the third image that they really dont it very flat so for 40 pages or more we advise perfect binding for a professional and slick finshed catalogue.
A5 Books
4pp Cover onto 200gsm Uncoated
Matt Lamination to outer
72pp Text onto 120gsm Uncoated
Four colour throughout
Trimmed, collated and square backed wire stitching