Print Merge Info

I've never had to use the print merge feature in Corel but I'm sort of familar with it because I read through almost every post on these boards because I never know when I might pick up some information that could be useful. I'm about to set up (3,682) 6" x 14" signs with three variable data fields. I need these signs to be ganged up inside a 4' x 8' area. I'm using a large format printer so the file will need to go through a RIP instead of sending directly to the printer.

Jeff H. has a nice tutorial showing how to set up the variable fields but I'm wondering about the imposition part of it. I remember trying to use print merge in the past and found that odd paper sizes gave strange results. At the time I was trying to print to a PS file for importing into a vinyl cutting program but I ran into quite a few problems with the objects being placed all over the file. I'm thinking I would be printing to PDFCreator to make a PDF that the RIP can output.

I know X4 has new features for the print merge so am I on the right track here and does anyone have helpful suggestions on what I need to look for as far as possible problems I might encounter?