To me, FT3 is a way to find and/or sculpt new worlds, rather than detail existing ones. It's quite a lot harder to use if you already have lots of ideas already set in concrete.

It might be easier to start this in Campaign Cartographer by creating a world sized map (each map unit is either a mile or a km), and drawing the predefined parts of the world as simple land shapes using the native land drawing tool. That way you can try out land shapes for the rest of your world relatively quickly, rather than sculpting and resculpting in FT3 several times over, which takes much longer.

That's transparency acne.

Sometimes when the pixels in an overlying texture are the same colour as the pixels in the underlying texture, and there is a glow, edge fade, inner, or bevel of either type on the overlying texture's sheet, the rendering engine gets confused and fails to recognise there's anything there on the overlying sheet. So it's read as a pinhole exactly one pixel in dimension. That's why the holes are all the same size.

I have noticed that this is quite frequent with SS5, where all the fills have lots of little black marks, and are all quite similar greens and yellows.

You can try placing a new sheet with nothing on it between those two sheets which does sometimes work, or if it doesn't, copy the overlying polygons onto that new sheet along with the sheet effects. That can also sometimes work without further effort. If that doesn't work either, try changing the fills of the new copy polygons to Solid, and a colour that isn't in either texture. If you have to go that far you may need to increase the width of the edge fade to make sure it doesn't show through.

Try clicking the Text Specs button next to it |CC2TSPEC|. There's probably a very tiny number in the Height box. Put something sensible like 10 in there and try again.

Make sure you have checked the little box called "Send me the monthly newsletter email with any applicable offers" on your Profile tab, and check that your email address is correct. That way you may be able to get it at some point with an offer.

Black Friday is often also a good time to keep an eye on prices.

Ah yes, that will happen if the whole world has been exported. If you had exported it at a lower resolution the detail would be even less when zoomed in that far.

Here is a small group of islands on my FT world

And here is the same group of islands on the CC3 map I exported yesterday (when I exported the entire world at Fine resolution).

This level of detail is fine for the world map, where an excess of detail on every inch of coast would only serve to make the map incredibly slow in CC3, and would be completely unnecessary for the world map in any case, with most of the detail being wasted on our comparitively weak human eyes.

If you want a detailed map of the islands zoom in to the FT map and export again to create a regional map of that area using the same Fine resolution.

This is the result of exporting just those 3 islands from the FT map while I was zoomed in to them.