The screen edges code has been tweaked in the 2014-05-20 WIP release and works better. Detecting a bottom edge touch is now reliable.
I’m not sure what you mean here. Are you asking that top screen edge touches get ignored on the left half of the top edge where the application menu is? If that’s your question, that’s not possible either. The actual display of the menu is up to the Apple frameworks, and I am unable to determine how wide it is. Also the right side of the top edge gets filled up with controls of different sorts, and I don’t know what is there, either.
Using the top edge is probably only practical for the secondary screen. It’s included for the primary screen mostly for consistency.
As an alternative, you might consider getting a mouse with lots of buttons. Logitech has some good candidates.