About the second question.

2 is the limit for drawing tools. Other than that you will have to manually copy them to other sheets.

I've used a similar method in my DD4 example map (sorry - can't show you that yet) - not Color Key, but a sill sheet. I have sills that match the walls. The windows and doors only cut the walls. When the sill appears in a doorway it looks like a threshold. The trick is to not put anything more than a slight glow on the sills so the eye interprets it either as a windowsill, or as a threshold, depending on context.

I found the notable blog, though I don't know if this will help you or not. https://rpgmaps.profantasy.com/exporting-coloured-topographical-maps-from-ft3-to-cc3by-andre-franke/

I've got the best results by picking a world that's sort of right in the general essence, and then editing it to make it more like the vision it generated in my head.

Sorry for hijacking the thread quite a bit, RyanosRealm!

That's @WeathermanSweden's work ;)

I can't say for sure. Maybe one of the other team members can shed some light.

I believe similar discusions have previously revolved around the matter that despite much talk there still isn't a standard file format accepted and adopted across the industry.

If you hide all but the floor sheet you can then copy the floor you have drawn onto the walls sheet. Then hide all but the walls sheet and use the Change Properties button to change the fill and line width of the ex-floor. Giving the polygon a line width will make it into a wall around the same shape.

Make sure you also change the layer to WALLS as well as the sheet, and you will be able to cut doors through the walls with the cutting symbols.

I walked right into that one! LOL!

Mountains will be larger than life in an overland map. You can probably just about get away with the existing ones, but don't go too much larger or the whole continent will start to look like a small island.

Do you mean scale it?

If you do, open the Fill Style dialog and pick the fill you want to alter from the dropdown list,

then adjust the hieght and width accordingly.

Yeah, roundish or shorter would be good.

They look weird if they overlap on the same sheet, but ok if you use a second sheet for the ones on top.

In a top view style there's not much point in overlapping them too much. It's not like an isometric view.