Hide intermediate values in a function
For the intermediate values in a chain of statements that only one final result is useful afterwards, you could hide all the intermediate values in a function, to not use spaces in the main stack.
If the function is pure (doesn't involve I/O), and the argument isn't used, instead of defining the function and immediately calling it, you could save one item in the stack by defining the function to apply the argument as a function to the supposed return value and delaying the call to where it is used.
That is, for such a function, its application and further uses of its return value:
w WWwwww WWWw WWWWw v
Apply the argument to the supposed return value in the end of the function, remove the application, and swap the function and the argument when you need to use the supposed return value later:
w WWwwww WWWw WWWWw WWWWw v
If you try them as full programs, they give different results, because the function calls Out which isn't pure, and they ran twice for the two calls.