the parameters you need to adjust are more likely the ones in the IMAGE SAMPLER (ANTIALIASING) rollout wich manages the sampling geometry details, texture details and stuff like that.
this is quite different from global DMC sampler wich is more involved in manging the sampling of blurry reflections/refractions and stuff like that..
actually i think you need some basic concept about sampling, antialiasing and more..
try to google for this.. there is a lot of stuff online.. like this example links..
you may also want to read the fantastic manual on the chaos group website?
theory:
http://www.interstation3d.com/tutorials/vray_dmc_sampler/demistyfing_dmc.html
practical implementation of the concept:
https://www.youtube.com/watch?v=pak8wx7KNEA