All texture files follow the naming convention recommended by Unreal Engine. They all start with T_, followed by the main image name (ie Medical_Ahead_Up, Engineering_Left, etc), then the resolution of the file (ie _4K, _2K, _1K, 512) and finally with the type of image file (_A for Alpha channel, used in all type of decals or _D for Diffuse aka the color image, used in color or greyscale decals).
All of the example materials ship with the 4K files set. If you want a different resolution then I suggest duplicating an existing Material Instance of the 4K verion of the decal you want (appending the resolution you are changing it to, like 2K, 1K or 512). Then you will need to modify the textures used in the material to select the specific resolutions you are looking for.
I will be updating those packs so they have the same main decals names as this one does (see the List of Decals, next). Their styling will remain the same though.
Watch a demo video here: Scifi Decals 3 Demo.
For version 1.0 of the Scifi Decals Style 3 asset package. Updated April 23, 2024