Hi @John_Ruggero
it seems that there is, for mouse clicking/selection, an upper staff zone, a lower staff zone, and a dead zone in between, and they are independent of protruding elements on the staves. The accuracy is of course bigger if you zoom in:
For near positioned or even overlapping elements, you can also use the shortcut
Shift + alt/option and, with the shortcut pressed, clicking several times selects every time something different 
If you work in Galley view, you can expand the ideal staff gaps to something like 200%, so you have more space for your selection, because this increases the dead zone between the staves for the Galley view (and doesn’t affect the layout of Page view).
