Hi, Bullfrog. I've seen your website. Cool.
If you're interested in trying other Harper's puzzles see post #1 re the Dropbox link formats.
The earliest is actually 2011-01:
For solutions, substitute "sol" for "puz".
The "%20" translates to a space in some browsers. No worries, just change the date.
There are a few missing months when the magazine didn't arrive. I can't give you a full list here, but might figure out a way.
They aren't all this easy. Give them a shot.