When I decided to try to figure out the diffuse module I printed out all the presets for comparison just to get a sense of what was changing and where to produce the effect.
Someone just starting out might find this helpful as a reference as you go through the various options … Diffuse.pdf (593.9 KB)
I went old school and printed them so I could lay them all out in front of me side by side… I found this the best way to review them across the spectrum of preset and find what sliders were used to target what…