The first reason you’re not getting a straight answer about this is because it depends on what you’re developing for if you’re developing for mobile you have to worry about polycount obviously but you also have to worry about draw calls for every material you have it counts as a draw call. You’re developing for Xbox one or Playstation you should still keep an eye on your draw calls and materialsbut not as important as how expensive your materials are in computations.So you need to know what you’re developing for first. After that it’s a balancing act obviously as an artist you want things to look as good as possible . In your case I would go with a single material at the larger size. At a 256 resolution it’s not much and it’s a pain in the ■■■ managing 6 materials on a model especially if you come to find out later on that you need to do something that affects all six materials at the same time. I know because I have a model that has six materials on it that are 2048 textures and plans changed on it down the road in our game and I ended up having to make the model look like it was printed and it turned out to be a real pain in the ■■■.