It depends on 2 things. How large you intend to use this map, and whether it's practical to scale the river width up when there are so many of them.

For instance, if you want to have it as a large export that is 10,000 pixels on the long side you can get away with more rivers of a slightly wider line, but if you only want it to be 5,000 on the long side when exported, it might be less crowded with rivers if you delete the tributaries and just have the main rivers fractionally larger.

Best thing to do is to export it at the size you intend to use it right now and look at the rivers - see if they are a) visible, and b) cluttering up the map too much, or just about right.

This is also a good time to make sure they all reach either the coast or a very large lake/inland sea.

The Herwin Wielink colour palette on your map isn't really helping you, with only a single row of relatively dull blues to use, so here it is again with a more balanced colour palette attached to it - to give you more choice with your labels (and only if you want it with this modification).

Hi Brian! :)

The most important thing to remember with lables is contrast. If you turned your map black and white the map itself would be all shades of grey, ranging from a very dark grey to a very pale one. To make text stand out from it chose either a very pale label colour with a very dark glow, or a very dark colour with a very pale glow. The kill-all solution is to use the palest and darkest shades of grey - one for the text and the other for the glow.

Drop shadows don't generally work very well for readability, but can look good on a title sometimes.

Your labels are pretty much mid-tone, which is the most difficult colour to make stand out, even when you intensify the native white glow.

I recommend picking lighter or darker labels, and maybe using an Outer Glow instead of the slightly less tidy Glow, like this.

Or like this.

You could use both on two TEXT sheets - one way for the title and the other way around for the map labels.

Ah ha!

I forgot to switch off the antialias.

For some reason you need to have some antialiasing going on.

Try about 20-33%

That definitely shouldn't be happening at zero antialiasing. Please can you report it to TS for me?

Great first map in the style :)

I wouldn't use the same symbol size for such a gigantic map. You would barely notice them on that scale. Perhaps create it at 1/4 of the eventual size? It's difficult to say what would look good, but why not try a couple and see how visible the symbols are. Remember that at world scale a single ridge symbol might indicate a small mountain range.