I'm running the client on a Mac, if that makes a difference.

I haven't been able to figure out how to alter the fonts into a more readable
size/color. Can someone give me a little help with that, please?

As wonderful as the client might be, I can't keep using it with the tiny font
and blue-on-black defaults.

You can change the ansi colors used by the client, escape -> settings -> others
-> ansi colors
then pick the color you want to change.

As for fonts control click on the window tab name, e.g. Generic (yes I know
control click isn't a mac thing but this is how the client works) and pick
Select Font.