Help scaling text size according to resolution

[ghost]

Hello,

I'm new to OSG in general, so this is question may come off as stupid, but I couldn't find out what the best way to achieve what I wanted is. I have an osg::Geode with 2 different blocks of osgText::Text that needs to be displayed on the screen of a full-screen application. The problem is that it looks fine on 1920x1080 displays, but when I tried it on a 4k display, the text is small, almost to the point of being illegible. So, I want to scale the text size according to the resolution, so that it stays approximately the same size.
Now, I have a solution of sorts where I just scale it using text->setCharacterSize() and the resolution. But, I feel like there might be a better way to do this. One problem is that some of the displays can also be vertical, so just scaling the text using osg::Matrix::scale() ended up with the text going out of the screen on the vertical display. What would be a good way to do this?

On another note, what exactly is the difference between the CharacterSizeModes()? Couldn't really find any documentation about that. As far as I can tell, using SCREEN_COORDS scales it down according to...something. What is that something? Again, this is probably because I'm new, so sorry if this is a stupid question. :P