Some of the turbo props(metro3 case)have a graph based on 'Full reverse'stop distance..I'm not sure if the Dash8 has JAA info in it's perf Data(it should as Canada has adopted JAA as a norm)...JAA info gives 'credit' for reverse(distance)although the gen thought is that anything above reverse idle,in the eng/out case/rejected T/Off,would provide adverse YAW???
Canada's' coeficient of friction' runway charts afford 'credit' for symmetrical discing/reverse(canada's AIP)