Keep in mind, the tutorial was written for P8, which does not have render based gamma correction.  The basis of this exercise was to balance Gc and HSV exponential for optimized rendering for realism.  It did require gamma to be lowered to approx. 1.3 and HSV increased to compliment the conditions.

@ErickL88:  BB did mention in a previous post, if you are using PP 2010+Gc+IDL, you could literally strip your figure of any MAT Room node work, reconnect just your texture images, reset your diffuse_color to white & diffuse_value to 0.8, and render.  I am paraphrasing, of course, but simplifying your nodes will improve texture quality under PP2010.