At the end I made a new layer under the roofs and took a soft brush with black and 35% opacity to draw a slight shadowline under the left tilted roof in the front. For the crest at the front I just copyed a smal fitting part of the crest of the tilted roofes and fitted it in at the top of the front triangle. Then I duplicated this layer, flipped it horizontally and gave it a slight overlay of black by 16% opacity. I fitted this to the front of the tilted roof and cut off the parts which are not needed anymore and outlined the lower edge with the outline color of the specific roof. Made two other duplicates of this crest and aligned them and combined the three layers to 1 layer, which I turned by -45° vertically. I went back to the A-Tile and copyed the very top of the roof (crest) and pasted it as layer above the tilted roof. I duplicated this layer again and flipped it horizontally and gave it a multiplied black overlay of 35% opacity, so it looks darker. Then I used the 'tilt' tool and tilted it by -45° vertically. Skaled it 50% in height, duplicated it as much till I got 3 times 48 pixels in height and combined the layers to 1 layer. I copied the roof tile from the A-Tile of Outside, turned it 90° clockwise. Click to expand.To answer your first question(s): I used Photoshop.
