Output file format
What do you recommend as output, Postscript or PDF?
We generally recommend that you use Postscript when possible, usually this would generate smaller files and faster print outs.
When it comes to offset printing you could minimize the risk of unnecessary conversions between formats (from PS to PDF and then back to PS again) by using Postscript.
If you are certain that the offset printer has “native PDF” as a print description language, then no conversions would be required and this solution would be faster than using Postscript.