As alfabus said, I think you’re barking up the wrong tree with Psylos on a Big Hit. Having said that, I have seen a fellow in london riding a Big Hit with a set of 100mm RST Gila forks that looked like they’d been liberated from a Spesh Hardrock. Yes, it did look ridiculous.
The Psylo wasn’t Rockshox’s finest hour. They have a problem with the plastic internals absorbing damping oil and swelling, making the suspension spike horribly. The only workaround is to drill out the valve to fit, which TF Tuned will do as part of a service. They weren’t overly stiff or reliable either.