sycamore,
Here is a picture of the fan-in-fin Blackhawk (the distinction between the older experimental Blackhawk and the newer production model was to use two words for the production Black Hawk, vice the "One word Blackhawk" back in the old days around the Sikorsky pilots office.
The drag brakes had no differential control effect, they were depoyed symmetrically. The Blackhawk needed no roll assistance, the roll rate was well over 100 degrees per second!