My vet had me re-train, via crating, my 2 sprayers (Sterling and Jim) . they each had a large cage with food, water and litter. They didn't necesarily like it, but they used the box!
then they graduated to the small room, and needed to continue to use the box!

Would I do it again? Possibly. Would depend on the personality of the cat AND the reason for inappropriate peeing. Never for a medical reason.

I am just happy to see that someone is actually trying to KEEP their sprayer and not just getting rid of them. At least they seem willing to try.