Hi Elvis,
Thank you very much! You are totally right, but I needed to post a compressed format to be able to upload it. In other case, images were too heavy and weren't able to upload. And, in addition, that pebbles color image were originally low-resolution, but it's the only one I was able to publish, due to copyrights, sorry!
Please, Elvis, could you confirm me if normal maps are also working fine, when maintaining the surface flat, without applying displacement? (In Unreal works fine and as spected, when you visually analize the normal map "sense" and compare with the plain-relief obtained result with applied normals, but with V-ray it looks strange, but maybe because V-ray doesn't use normal natively, but bump maps instead, is this right?)
If any of you want, you can send me any color texture and I will generate the PBR maps for you (and send them as high resolution and uncompressed PNG images), so you can "taste" it by yourself. You get free generated PBR maps and I get more feedback . Of course, we can do it through private messages, to preserve the images' copyrights.
Thank you again and best regards!