James --
In studying the anatomy of a bear from a broadside presentation, and in discussing it with Ryan Derlago, I have come to the following conclusion:
If you divide the area from the front leg to the back leg of a broadside bear in half, shoot for the exact center of the front half. On a normal adult bear that would be about six inches or so behind the shoulder. As far as elevation is concerned, half way up the body is best. Forget about the space the hair takes up on the silhouette, just be half way. That elevation is best whether you are on the ground or in a tree stand.
Of course, never shoot straight down because you won't get both lungs.
Good luck on your bear hunt this year.