I'll only comment that the two most experienced bear guides I know (one on big island black bears in British Columbia and one on brown bears in SE Alaska, both with decades of hunting) both advise against trying to "break down" a broadside bear with shoulder shots.
This is because they've seen too many hunters break only one shoulder without hitting vitals. This is because the hunter gets so fixated on breaking down the bear that they miss the center of the heart-lung area. Both guides advise shooting for the middle of the lungs, as no bear lives long with a big hole in both lungs. This has been my personal experience as well, with both black and grizzlies.
If a bear is charging there is no way to take out both shoulders with one shot.
