The Speer #10 manual is yer friend. They have loads including the 125gr HP, 140gr HP, and the 158 HP. I'll list the loading data with beginning data, max data, and max velocity for the 158's.
IMR4064 54.0grs- 62.0 grs 2841'ps
IMR3031 50.0grs- 58.0 grs 2865'ps
RE7 51.0grs - 55.0grs 2901'ps
I've tried the 158's out of my Remington Classic in 350 mag and accuracy was extremely bad. I was lucky to keep the bullets on a 36"square plate at 100 yds. While I have the components, I never tried the Speer 180gr flat nose with SR4759. Data is like above
SR4759 24.0 grs- 28.0 grs 1926'ps
Might give that a run of you have the bullets.