I would recommend making a Python script to create the geometries for you. You can write your Python directly in the Psi input file, and Psi will execute it at runtime.
Constructing good Z-matrices for non-covalently bound systems is always a pain, especially when there’s no “obvious” way to choose what interfragment coordinates you should use as your internals, and especially when you need to deal with molecules as large as the ones that I think you’re working with.