adjusting the shock settings doesn't stiffen the ride, as the car is held up and sprung by the spring rates. The shock only slows the compression or rebound of the spring itself. IMO, he's correct in looking for a stiffer spring to accomplish his needs. Of the options listed, I like the Stance GR+. I wouldn't go with the pro's, I don't think the helper spring is worth it, and it's the only upgrade you get for the extra cost.
I would also consider this option: when is it rubbing? every bump or just cornering? If just when cornering, consider maintaining a softer spring rate and increasing the sway bar stiffness. Just a lateral thought.
I'm sorry you suffer from cranial-rectal inversion.