You need to use the right house tools. There are separate house tools for metric (the SS5C m ones) that uses frills that are scaled for metric maps.

These tools should work just as fine on Metric as Imperial overland maps.

I know they don't work as well in small-scale maps as large scale maps though. What is the size of those maps (the dimensions you entered in the new map wizard)?

Also, have you modified the symbol scale from the default value in the map?

In any case, if you are not happy with the distribution after running the tool, simply undo once, as this removes the trees but leaves behind the background polygon, then immediately run the Draw -> Symbols in Area command. This will bring up the dialog with the same setting the tool just used. Then modify the distances in the pattern section, hit ok, and pick the background poly you created with the tool. This will fill it with your new settings. If you still didn't quite like the result, undo once to remove the trees you just placed, and repeat. When you find a setting you like, you can save it (but I recommend NOT saving over the existing setting used by the tool, make your own)

Anything that makes two entities do it by adding both a main entity and the outline. In Sue's first screenshot above, you can see there are two buttons, "Properties", which lets you change the settings for the main entity, and Outline, which lets you change settings for the outline entity (Which doesn't actually have to be an outline, it was just named like that because that was it's initial purpose)

When you are dealing with with and outline entities, just change it both places. Keep in mind that the values were probably just a tad different originally, so keep that difference in your changed versions.

This happens because the RGB Matrix effects is vulnerable to TA as well. It won't make gigantic holes, since it doesn't do any edge effects, but it still need to figure out what parts to color, so the same pixels that make giant holes with edge fade are left out by RGB Matrix, leaving the edge fade to produce the known and loved TA holes.

Personally, I feel it needs more clearly defined streets. The continuous cobblestone fill looks a bit weird and unnatural to me. Even if a city did use cobbles for all it's streets (which is uncommon in itself), having it wall-to wall everywhere looks out of place, especially in places outside the main thoroughfares, like back alleys and backyards.