I know that I have been able to adjust paper sizes using this method. Especially when I have been using continuous rolls for invoices and I got it to work within Great Plains Report Writer. This is right out of the Report Writer Manual from Great Plains
Page size
Keep in mind the total size of the page when you’re creating the layout for a
preprinted form. A report layout is based on 72 points per inch, and each
pixel on the report layout represents one point. If you are developing a
preprinted report for standard US Letter size page, the total size for each
page of the report must be 612 by 792 points (8.5 inches by 11 inches).
Remember that there are no built-in margins for a preprinted report, so you must
account for any margins you need for your report.
To determine the total size for each page of a report, add up the sizes of
each section of the report. You can find the height of a report section by
clicking the handle for the section in the Report Layout window, and
viewing the section size at the bottom of the Toolbox.
If the total size of a page for a report is larger than the maximum page size,
extra pages will be generated when the report is printed. If a page only
slightly exceeds the maximum size, an extra blank page may appear in the
printed output. If the total size of a page for a report is smaller than the
maximum page size, the report may “creep” as it is printed. When a report
creeps, information on subsequent pages of the report will tend to move up
as pages are printed.