ssrs 2008 r2 print on letter size paper

In an SSRS 2008 r2 report, I would like to make certain that the report prints on letter size paper
when the report is exported to PDF. I know that the following is probably a 'formula' to figure out the
print option: Body + header + footer + margins <= report.

Thus can you tell me what you think the values are for the items listed above for the
report to print one letter size paper?