I still believe that toggle logic for Brush Preview and Brush Outline overlays could be improved or changed, but i don't know how exactly.
Currently the only usable setting for all brush tools is to enable "Outline: Both" and "Painting Tools with Preview". In this scenario i can see both Preview and Outline in Brush, Pencil, Copy Brush and outline in Remove Brush, Finger Brush. Caps Lock could be used to turn off outline during painting with normal brushes. This feels OK in most situations.
Caps Lock was perfect to simply turn on/off brush outline, but it not too perfect with new additional brush Preview mode and creates some limitations. Here are problematic situations:
Outline On / Preview On = can't use outline only mode in Brush, Pencil.
Outline On / Preview Off = can't use Copy Brush because can't enable preview.
Outline Off / Preview On = can't use Remove Brush, Finger Brush until press Caps Lock
PhotoLine really needs quick independent toolbar toggles and hotkeys for Outline/Preview overlays (or for Outline/Center/Preview).