How to "guarantee" Lilypond pdf (letter) output with sufficient margins for 3-hole punch?

[Kenneth Wolcott]

Hi;

  How to "guarantee" Lilypond pdf (letter) output with sufficient
margins for 3-hole punch?

  I'm looking forward to having a method of "guaranteeing" Lilypond
pdf output for letter (not a4) of my engravings such that the
resulting printout can be three-hole punched (on both sides
potentially) without making adversely affecting the visibility of the
pdf.

  This "procedure" or "process" might be needed retroactively as well
as for a new engraving project.

  I know that this might be a proportionate value so I'd have to
adjust it if I specified (or changed) a global font size.

  I guess what I'm looking for is the equivalent of "indent" but for
every system.

  I'll look again to see if I understand "margin"-related settings...

Thanks for hints...

Ken Wolcott