If they are already only 1 pixel wide, you need to double the resolution of your textures, and keep them 1 pixel wide.
It might help if you always make them in a separate layer in Photoshop, give this layer about 20-50% opacity, and set it to "Overlay" or "Color burn" blending modes. After that, you can try duplicating that layer, applying a 2-pixel wide (or so) gaussian blur to it, and setting this new layer's transparency mode to "Multiply" with an even lower opacity. It's not the best looking thing in the world, but it helps you come up acceptable low-res hull plating textures quickly.