Convert an Adafruit graphics library sketch to use U8Glib library instead?

I saw a nice OLED Clock project (link below) which looked a good use for a 0.96" I2C 128x64 OLED display I recently bought from ebay. The author uses the Adafruit_SSD1331 library, and although our display modules look the same, his evidently works fine, and (of course) mine doesn't. After a long slog I found that mine does actually work ok when used with the U8GLIB_SH1106 library examples instead of the Adafruit library, which isn't really much consolation if I can't use it for the Clock project and it ends up indefinitely back on the shelf.

So how feasible is it to convert an Adafruit graphics library sketch to use the U8Glib library instead?

Just in case someone has already solved the Adafruit problem - the Adafruit library does write to my display but only shows scattered pixels with no recognisable underlying pattern, although I noticed it doesn't seem just to be a random pattern because it reproduces the same 'starry night sky' even after a Nano reset. My i2c has pullups, and the display address is 0x3C, which matches the Adafruit reference in the sketch.

OLED Clock link: