Many of the old standards no longer apply because the software has gotten better.  Anything involving IDL in the most current Poser iterations do better, render-wise, with diffuse_values less then 100%.  The lights and shaders interactions are more realistic and respond as they should without introducing hacks or faking certain conditions.

IBL introduced a level of creating ambient lighting realistically based on HDRI data plugged into the lightsets.  But with the introduction of IDL, you no longer need to fake ambient lighting.  Place a self lit skydome into the scene, plug in a good HDRI, and you have all the most realistic ambient lighting you can ask for.