Fitting ridge capping:
When working with wide pan roof profile place your ridging where it will sit center of the roof ridge board and carefully mark out the section of the ribs to be cut out to allow the ridge capping to sit down flush with the roof ribs and close off the roof to wind driven rain.
If using a lead or similar ridging for corrugate roofing use a hammer to form this edge into a protective weather barrier into lower corrugations.