So far it looks like a single macro holds at least 100 lines. Possibly more, I'm getting sick of writing extra lines. All of the same macro options exist from FFXI, like /equip and /action (basically WS). There's also a macro for changing your equipped abilities, so if you're changing weapons (changing classes) you can automatically equip all of that class's abilities in place of the ones from your previous class.
Very promising upgrade over FFXI's macro system, I'm very happy to see it.