After a lot of trial and errors I finally came up with a pleasing "Rock" object population.
Unique Variations is at 30 for rendering, probably best to crank that to the default 100. The mosses mask is based on a image shader (provided; and yes I forgot to invert it lol) of some contrasted moss turned into a matte, so don't forget save that and replace the image mask for the Moss Controller in the rock object.
