The decals can have the scale command added, so you can basicly have a very large decal, tough as you scale it, you may loose definition, if your original image is not that big.
I'm using a 4x4 16 images with not standard definition, like 512x512 or 1024x1024. As an example, for the "starts sunday", my final texture has got 2880x1920, with each block having something like 715x480, which gives a good margin for scaling them in FPSC without loosing much quality. This is why I've called them "High Quality Decals"
Hope this helps!
Currently working on the MindTrix Entry:
