The guy at the meat counter in Akron who said to stop trimming so much fat

Last month a customer at my counter in Akron stood there for a minute watching me trim a whole brisket and then said I was cutting off half the flavor along with it. He told me his family ran a butcher stand in Cleveland for 30 years and they never took fat below a quarter inch because it bastes the meat from the inside (he tapped the cap with two fingers to make the point). I kept trimming thin out of habit because that is what the case looks like neat and pretty, but I tried his way on the next three briskets and the bark came out better with no extra work. Now I want to know how many of you leave the fat cap thicker than the book says, and does anyone have a number they stick to on pork shoulders?