if you want to tile your images on the model [defining materials like in the 3d raytracer apps], i'd recommend some smaller maps. example: you modelled a car, so the color map can be extremely small (map1), you'll need something for the windows (map2 with alpha), and a leather map/wooden map for the interior (3 and 4) plus, it's easier to access single maps with shaders than masking with alpha, so map1 gets a specular shader, 2 an alpha material, 3 and 4 a bumpspec shader.