They're bigger than I had imagined.
I might have to get smaller displays to make the custom PCB affordable. :-(

I've successfully individually control each segment of nine digits using two shift registers. I still need to implement POV so more than one digit could "appear" to be on at the same time. My current path is to have one shift register (and transistors) to drive the column of digits, and nine more shift registers (one per row) to "draw" the desired digits on each row for the current column.

Code in progress is at GitHub. Videos coming soon at my YouTube channel.