I found a company called Crystalfonzs that sells SSD1306 displays and even a dev board, very inexpensively.
I bought a number of display modules with ribbon cable connectors . This seems like a good route because while the connector adds expense, it allows the display to be changed and eliminates a nasty bit of hand soldering.
All the displays work. The libraries written by Adafruit and Sparkfun work well for the display size they sell, but modifying the code, or even rotating the screen is a bit beyond my coding level at this point.