You should check a pool supply/care store in your area. They can look at your pool and will best know how to care for your particular one. I am not sure about a soft set pool, but for my in-laws pool, we use LTM-Lithium Shock, 6-8 cups. Then we clean...
No the auto cleaners won't reach that "ledge" but it shouldn't be much of a problem to "sweep" since it is so handily located around the outside.
Have you tried doing the "sneaky" thing... call around to pool cleaners and ask them what equipment they use to clean the pools? If they have any recommendations for automatic vacuums? Trust me, as a house cleaner, if anyone calls me and asks for my ...