Sharpie or Cooper's?

I had a Cooper's Hawk patrolling the feeders at home this morning, and later saw a Sharp-shinned Hawk perched in Waterford. Both were juvenile birds, and it is still tough for me to ID them quickly. Here's the best resource article I've found on the topic, courtesy of Cornell.

http://www.birds.cornell.edu/pfw/AboutBirdsandFeeding/accipiterIDtable.htm