I've had good results with the Speer 350 gr. in my .458 Win Mag. I use H4895 with a Fed. 215 primer. I've not tried to push them overly fast, but run them around 2400 fps., and have had accuracy in the 1 1/2" range at 100 yds. I'm pretty happy with that, and the Speer bullet seems to be relatively tough.
Best of luck with your .458! They are a real hoot to shoot!