There's one potential drawback of this approach that you should be aware of. If you set the font size to 18-point, then move your realm over to a laptop with a single display, that text is still going to be 18-point. If you're only using the one machine, it's not an issue. However, if you will be switching between machines with wildly varying displays, it could end up just moving the problem around without completely solving it. In addition, once player access comes online, your players will have the text also showing up as 18-point. So it's not a perfect solution.
I just want to make sure you've got complete information on this and don't end up frustrated down the line for a different reason that wasn't immediately apparent yet.