The concept is that, u can set how many pixels would like to use in one blender unit and then compared this the faces area size.
i.e u set the pixel size in blender unit = 128 pix/1unit
and the script calculate how many and what kind of textures need to that faces area:
i.e. two peaces 1024x1024 and one 512x512 textures need. (u can set the max size of texture size too)
and than unwarp the uvs with uv island margins with pixel extends and baking.
This optimalized way avoid the different pixel amount textures for faces if u assigned a big texture before-and the end use minimum amount textures that u need(few memory and boot up the fps ).