I haven’t used PBR textures but my guess for R16 or R17 would be:
Diffuse: I’m not entirely sure about this one. I would have thought it would go in the color slot, but you also list a color texture so maybe diffuse goes in luminance?
Gloss: This goes in the texture slot beneath the roughness slider in a reflectance layer (click the arrow in front of “Roughness” to twirl down the option. Set the roughness slider to 100% to get the full effect of the map.
Normals: This goes in the material’s Normal channel. You may have to experiment with different settings to get the right result.
Specular: This goes in the reflectance layer’s Specular texture slot. I’d recommend deleting the default specular layer.
AO: this would go in the Diffusion channel.
If you can post a file with the textures I’d be happy to have a look.