I think it would be possible to do these one-sided roofs using shaded polygons.

Pick the roof texture from the list of textures in your map (click the FS:... box in the Status Bar, and then the tab called Bitmap Files. The Fill Style Name dropdown should contain that roof fill somewhere in the list). Then use the polygon drawing tool |CC2POLY|on the right hand toolbar to draw the roof pieces.

When you've drawn all the roof pieces right click the same polygon drawing tool and pick the option "Shaded Polygon (Angle by Edge)", and click all the pieces at the bottom edge. This will align the fill and shade the roof pieces. If the first rooftop you click looks way too bright or too dark undo (CTRL+Z) and initiate the tool again (go for the same shaded polygon opotion in the right click menu). In the command line you will see an option to change the angle of pitch. Type a number of degrees that is different to the default 45 degrees and try again.

I can't see the outline you mentioned earlier in your screen shot, but if you want to add an outline to a polygon (roof piece) you can do that using the Outline tool |CC2OUTLINE|on the right hand toolbar. If you want an outline other than black right click that button.

When you fractalise smooth polygons they become straight ones again, so you will have to make them smooth again if you want them to be smooth polygons.

That's good :)

To put the effect on the whole map add it with the Whole Drawing radio button selected.

Depending on the type of map you are making...

Dungeon style symbols are usually imported at 100 px per map unit

City symbols are usually imported at 40 px per map unit

Overland symbols are usually imported at 20 px per map unit.

So it really depends on what type of map and how big you want your shield.

Ah, I see.

Maybe generate a temporary grid using 'Hex or Square overlay' in the Draw menu, and count the squares?

CTRL+Z to undo the grid once you've counted.