[mkraft]

The question here is whether your printer actually has a definition for the
6 x 8.5" paper size.

Thanks. How would I be able to determine that? It's an HP Laserjet, so I
assume it's as versatile as most printers in handling different paper sizes.

If not, and if you're setting it up as a Custom size,

In Word, 6 x 8 1/2 would have to be set up as a 'custom' size, wouldn't it?

Instead, set it up as Letter (or the closest larger size) and increase the margins
accordingly (including the required gutter or different in Mirror Margins).

Can you explain this a bit, I don't think I follow you. Do you mean to use
a standard (i.e., non-custom) paper size and simply adjust the size of the
table to conform to 6 x 8 1/2? If so, what about footnotes, headers,
footers, etc.?