Constant cable tension, zero spots where the delts get to coast.
Keep your ribs down and don't arch your lower back to finish the press.
Pressing overhead from low pulleys means your delts fight resistance through the entire rep, including the bottom position and lockout where free weights let you rest, and your triceps still finish the extension. Standing between the stacks with each hand on its own handle also means both shoulders press independently, no strong side quietly bailing out the weak one. It earns a place as an overhead press that keeps tension constant and exposes imbalances in the same set.
Dumbbells let you load heavier, cables keep tension on your delts at the bottom and top where dumbbells go quiet. The cable version shines for higher-rep pump work and for keeping both arms honest, since each presses its own stack.
You're leaning back to turn it into an incline press. Tuck your ribs down, squeeze your glutes, and if the arch still creeps in, the weight is heavier than your overhead position can currently handle.
On or near the lowest setting, so the cables pull down and slightly behind the handles at shoulder height. Starting with tension already on the stack from rep one is the whole advantage.
