Butterfly Surface Forces - Function Object Implementation Help

I could use some help implementing a Butterfly function object to solve for surface forces in a CFD environment. I see the “function_object” that feeds into controlDict solutionParams but I am uncertain how to use it properly.

I’ve had some success getting probe pressure translated to normal forces on mesh faces but the way I’m doing it seems clunky and requires manually matching probes with the object mesh based on proximity. Probably missing or double-counting pressure contributions.

Since the approach I’m using doesn’t account for shear forces and possible missing pressure contributions I would rather use a native OpenFoam function object to accomplish the calculations. Open foam has the “forces” function object that looks perfect for what I have in mind. https://www.openfoam.com/documentation/guides/latest/doc/guide-fos-forces-forces.html

Any guidance on how to implement and recover information from a function object like this would be incredible.
Thank you,