Ask-a-Dave's-Gardener: Pruning serviceberry , 2 by f0xgl0ve

f0xgl0ve wrote:
Our Autumn Brilliance serviceberries, planted about 12 years ago, are awkward looking. Early on they grew quite rapidly and, not knowing any better, we topped them. We did some pruning that helped correct the waterspouts that formed. Now they are too tall and congested at the top, with the lower branches dying out. How and when should we prune them to shorten them by about 1/3 and make them more graceful?