As I already stated, the maximum safe pressure for your revolver would be around 17,000 psi. Currently available 32-20 Remington ammo run at 16,000 psi in a rifle and should fire in your revolver without issue, probably at pressures of no more that 12,000 - 14,000 psi. Anything under 16,000 psi is fine, but there is no need to go beyond 10,000 12,000 psi to shoot at paper targets. It is your choice of what powder you want to use as long as pressure not too high.
No one on the Forum can tell what condition your revolver is in, so these comments are meant for a fully functional S&W with on issues or damage.