Are there any good discussions on map labeling that folks could point me toward? Here is my situation:

I have been working on the world map for my current fantasy game. I would like to have the "big" map of the whole hemisphere be labeled, and then just crop sections like the upper left 1/9th (more or less) for specific areas.

I have encountered several issues.

1) What looks good zoomed out is overwhelming when zoomed in, and what looks good zoomed in is invisible zoomed out.
2) How do I distinguish between political labels (a country name or city name) from a geographical feature (a river or mountain) from a descriptive name that isn't really political or geographical (goblins)?
3) I make continent labels bigger than nation labels bigger than city labels, but how big should a label for a river/lake/mountain/desert be? What if it's a HUGE desert? What if it's a teeeeeeny tiny river?
4) I considered using different colors for different label types, but the color of my map varies in luminosity quite dramatically. I have to have dark text when the map is light and light text when the map is dark, so that makes it impossible to use the color of the label text to mean something.

I am sure that I am not the first persopn to encounter these issues. If you take a look at my Archaea map (which is roughly the top left 1/9th of my world map), you can see how I am currently dealing with these issues. I am interested in any advice or suggestions anyone might have.