Thank you for the kind words!
I do seps in PS and sometimes for metallic paint reproduction, after the paint separation is complete I will contract my selection as to not affect the edges closest to the outlines, then apply a gaussian blur.
It kinda gives the illusion of the soft glow in the reflections of a metallic paint job. For chunky flake I will "spray" highlights using the dissolve option. This can be blurred as well to get a glow.
I am terrible at explaining crap so I hope this may help anyone interested.