Hi, Tim:
Yeah, there are a number of peculiarities to PDF Export that I hope can be addressed, as it's one of the most useful tools in the Composer toolbox.
Sherry directed me to a program call PDFTools (
http://sheelapps.com/index.php?p=PDFTools.HomePage) which is a dandy set of freeware cut-and-paste, mix-and-match tools.
When you end up with a set of partial .pdf files from the export or one with duplicate pages at the end, PDFTools easily handles the trimming and assembly.
I've used Composer's PDF Export together with PDFTools to compile score books for three musicals I've got happening next summer and the printout is phenomenal -- very high resolution and very crisp.
Compared to earlier versions I did using PrimoPDF as a virtual printer in Composer, the native PDF Export is head and shoulders above.
David