I will try your method.
Nevertheless, are you sure my method I wouldn’t reduce draw calls?
I thought that using a double mask I could use one master material that would contain all the terrain masks (river, mountains, valley, etc.) packed, then I could select which part of this terrain masks is shown in a certain tile by masking the masks and displaying only the part that belongs to that tile. It would still be just one material, so I guess it would be 1 draw call for all the tiles combined? It’s like a texture atlas which is just one draw call too. Isn’t this right?
Also, what texture quality do you consider an equilibrium between quality and performance for large tiles? I read that 2k would do alright? Maybe 4k?