From what I've seen in 6 years of carrying is that it takes VERY little to conceal from most people. There is an old saying, " you can't see the forest for the trees", that sums up the vast majority of the people who don't carry, about those of us that do carry.
To hide your gun too deeply, really makes your gun about useless in a SD situation. That is unless you are VERY good, and somewhat lucky in reading the situation around you.. (action beats reaction)
My .02 cents and nothing more.