So if you want to use your own Substance generated PBR textures in Octane / Cycles. Just replace the "Base-Color", "Metallic", "Roughness", and "Normal" Bitmaps in the material with your own and you should get a pretty convincing result.
I am aware that especially the roughness is not mapped 100% right in Octane (since its not behaving linearly). If you want to tweak it further I would suggest tweaking the gamma of the roughness input image.
Implementation in Cycles was pretty easy since it provides the new Principled Shader that is made for ease of use and and the PBR workflow.
For Octane for C4D v. 3.06.1 and newer
For Cycles 1.0.0202 and newer
High quality subdivision surface hand modeled magnifying glass
Materials and Textures
OBJ mesh for usage in other software