Hi Fori, glad my pack can help you to create your own tileset
So, to anwser your questions in ordre :
1 - For the "double" level of walls, there's ( in my knowing ) only one way : subwater walls. I can try to configure the tileset definition to obtain that this or this wall will be used for basement or basement+1, but not sure at all. However,
underwater can be add like wall or floor, as models reference, and these will be used for subtiles ( tiles placed at -1 ).
For the object, tiles and material files, they're ok like that. Just remember to add your user_wall_stone2 to the wall class in the tiles.lua.
2 - Yeah, there's a fix ^^. I'll before explain you how models are integrated to LoG2 graphics.
Firstly, models got "nodes" ( points in the space where are attached all structures of the model ). The first one ( Root Node ) is to define the basement of all ather nodes. After, you got the "MainObject" node, where is attached the fix structure of the model. On this one, will be also attached the texture of the model, based on the model construction in blender. Why these nodes are important in grimrock ? Because LoG2 take theses points to "place" them in the graphical space. So, like you undestrand, by modifying the placement of the structure node ( Root node ) you modify where grimrock will place your structure in-game.
To modify simply nodes/texture of the models, take the GMT from JohnWordsworth and open it. Select the root node and in the matrix, you can move in the space your model by the last column ( in order X,Y,Z ). In your case, you must up the ceiling by 0.5 point ( I think ).
So open the ceiling model with GMT, select the root node, enter 0,5 in the case at the second line of last column, click on "update node". Save the model and reload your map, it'll take effect immediatly. Readjust until it'll be good.
3 - For your textures ... before all, you must know that Grimrock1 and 2 are really differents with the shaders. That's why your mapping not lighted normally. To resolve it, you must modify the normal maps of your textures. For it, Leki gives us an excellent tutorial in 4 simple points
there. I advise you to use it
I hope these answers will help you