I recently acquired the PC-4 printer and cassette modules and wrote a version of my banner program for this model pocket computer. With only 544 bytes available, it was the most challenging version to code.
The PC-6 was the best (in my opinion) rebadged Casio pocket computer Radio Shack sold. I built a cable to connect the PC-6 to the FP-12S printer and updated my banner program using only 909 bytes of memory.
After successfully connecting a TP-10 to the Model 100, I did the same with the PC-2. I also updated the banner program for the PC-2. This gives the PC-2 the ability to print without needing those expensive plotter pens.