Tip number one!
Though I do return the correct header for a PDF, sometimes Explorer gets confused when downloading... So if you're running Windows, you may need to right-click a link and choose "Save link to disk".
Tip number two!
Some people may need to turn off the option in Adobe's Acrobat reader "shrink to fit" which may resize the grid slightly to fit your printer's printable area.
Tip number three! (for hex and iso)
If you want the hexes aligned with the other edge of the paper, just make your paper size "11 x 8.5" and print the result in landscape mode!
Via treasured patterns