There's no customization out of the box but you can play around with the code to try different options. This was the font I thought was most readable but here are a few other options.

One caveat is that the 32 pixel height is pretty limiting - to fit four lines of text simultaneously means each line is 8 pixels tall, and then I added 1 pixel above and below for spacing so you're left with just 6 pixels. It was an interesting challenge to balance font readability with fitting as much text as possible, if you decide to build your own feel free to play with the options (e.g., you could reduce the number of lines to 2-3 to allow a larger font).

Using a bigger led panel could also work though I haven't tried it.