That would be the actual size of your world. As with any map, it is important to know how large it is before you start mapping. If you are mapping a whole world/planet you need to know the dimensions of the planet.

I find a good style that is designed for large scale mapping. When mapping a whole world, you would normally want a style where you can do most of the mapping using drawing tools and fills, and not overly rely too much on symbols. A lot of our styles can do this just fine, including the default overland styles that comes with CC3+, but some are better suited for more local area mapping.

Don't try to add too much details. I usually think of my maps like those found in the school atlases. A map couldn't be bigger than a two-page spread, so it should be readable at that size. Details that are too small to show up at that scale, or would overly clutter the map is left out, these can be shown on separate zoomed-in maps of relevant areas. I like developing my worlds as a series of maps of different scale levels, similar to what is done in the community atlas.

The reason for avoiding tiny details are twofold. First of all, it reduces clutter in your map and makes the map readable when you view it zoomed out. Secondly, filling out a whole world with tiny details are extremely time-consuming, and almost always leads to mapping fatigue and a half-finished map that never gets finished.

Note that if a layer won't freeze, it is probably because it is the active layer. Make sure to set the layer you want to work on as active first (The first checkbox), then you should be able to freeze the other layer.

You don't have to reinstall the software. That preset is embedded in the map template, and can be regenerated from it. The preset is only needed if you need to re-apply it to the map for some reason.

To recreate the preset, start a new map using the right style, the CC3 Mike Schley Overland in this case using default settings in the new map dialog, then enter the :CC2SHEETS: dialog, make sure effects is turned on (otherwise the options are greyed out), simply hit the "New" button to create a new setting based on the current map, and name it CC3 Mike Schley.

This is a property of those symbols, standard behavior on the SS5 trees.

This setting is often configured for symbols that you may want to place along another entities, but should not go in the middle of the other entity, such as a alley of trees along a road (or in a dungeon, torches on a wall). It allows you to easily make sure all of the entities have the same distance from the centerline of the target entity.

The reason you don't see it every time you place a tree is that it is only triggered if you actually align the tree to something else. If it is placed in free empty space, there is nothing to align to, so this step will be skipped. To force this behaviour, when placing trees, move your cursor over a line/poly entity in your map, such as a road. You'll notice that once your cursor is over the center line of the road, the tree will rotate itself to align with the road ("aligning" for a tree may not be very obvious, but you'll see it rotate anyway), and if you click to place when it is in this state, you will get the Offset behavior.

If it just seems to happen out of the blue, for example in an empty area, there probably is a line or edge of a poly hidden on a sheet behind there somewhere. Even if you can't see it, CC3+ will detect it.

You can change the scaling of the fill.

If you click the FS indicator on your status bar to get to the fill style dialog, go to the bitmap files tab, and pick the relevant fill in the dropdown, you can change the values under "scaled" to change the size. Larger size means less tiling, but remember that the resolution of these fills aren't infinite, so they will appear pixelated if you set this too large.