Good to hear that you're making some progress with it!
I have a feeling that these two color displays work by displaying both RAM1 and RAM2 at the same time, onto two different colored layers of pixels. If one layer isn't set, you can get an odd blurry mix.
I forget the exact settings needed, but glancing quicky at my own notes to myself, I would suggest something like:
Black - RAM1: off , RAM2: off
White - RAM1: on , RAM2: off
Red - RAM 1: on , RAM2: on
So each pixel should be set with both 0x24 and 0x26 commands, to give it the appropriate mix.
I also have a suspicion that either the 0x21 / 0x22 commands will determine which RAM is being used, so if your example code is from a BW display, it may need a slightly different configuration to display both layers simultaneously.
Best of luck!