Which animal's vital organs do you intend to obliterate with said projectile(s)?
Personally, my go-to is a .495" round ball in a 0.015" greased pillow ticking 'sabot'. But that's not likely to work well with your fast twist barrel.
If I was in your shoes, I'd run the Nosler BTMZ for big game.
The BTMZ is a 300 gr .458" Ballistic Tip.
It's a well-constructed bullet in a good sabot, and has an excellent track record.
Nosler finally also released it as a component bullet for .458 SOCOM reloaders last year. Very good bullet.
My opinion on the Hornady stuff:
The FTXs have mixed reviews, and my own testing with .44 225s and 265s, and .458" 325s left me looking for other options. They would have worked on game, but expansion was too violent for my liking (even at velocities as low as 1,600 fps for the .458" 325 gr) and the lead core is very soft.
The .452" 250 gr FTX was designed as a muzzleloader bullet, and later adopted for .450 Bushmaster because of the working velocity. It's a good bullet, and a bit tougher than the 'handgun' FTXs. Not a bad choice.
If I had to choose a Hornady bullet to use, it would be the .44 300 gr XTP. It's a tougher bullet than the lighter XTPs, along with the extra mass.
The .45 cal 300 gr XTPs are probably as good, maybe even better, but I have no experience with them.