Swinging fly's at a 45 degree angle as you work your way down a pool is the best technique. Now that the water temperature is in the 50 degree range, dry fly's are working well. Begin fishing dry's from the bottom of the pool and work your way towards the top.
The Grand Cascapedia is in early summer flow at about 50 cubic meters a second and clear. The weather will be hot and humid but will break by the end of the week.