I’m fluffy and only carry 3:30 OWB or occasionally IWB (hopefully more of the latter.) My most common daily carry is a 26 with RMRcc and I’ve noticed no additional difficulty concealing in my usual garb - an unbuttoned cover shirt over a colored T shirt. But, again - I’m fluffy and am carrying in an easy position. Plus, I’m not in areas where I worry too much about not occasionally profiling.
For me, RDS makes no difference in concealment.