I have added this awesome tileset to NotEye 7.6.
http://roguetemple.com/z/noteye-img/tpp-dawnlike.png (
http://zenorogue.blogspot.com/2014/03/noteye-76.html )
I had a problem with walls: there are no tiles for wall endings. I am using straight wall parts for them, but this is not perfect.
Overall, I would recommend using the following arrangement for both floors and walls, on 4x4 tiles (each + is a center of a tile):
+---+---+ +
| | | |
| | | |
| | | |
+---+---+ +
| | | |
| | | |
| | | |
+---+---+ +
+---+---+ +
The motivation is that, with the current system, when using your tiles for the floor in a randomly generated map, I need to check the type of the four neighboring cells (to know whether my floor tile should use the connected variant), and then look in a table which says where each of the 16 possible cases is placed in your tileset. And then I do the same with walls, but the table is different.
With the system above it would be much nicer to program (I check horizontal connections and get the X offset, then the vertical connections and get the Y offset). Also there would be no ugly empty spots (which makes looking at the raw tileset more pleasant and the size of the image file would be smaller).