Hopadoc,

You need to take into consideration bullet construction. Today's bonded bullets and monolithics deliver superior terminal ballistics than those when the cartridge was concived. A modern bonded soft can penatrate deep and produce a large wound channel. Also, solids have larger metplats which a cavitation void is created as it plows through. No more .458 in .458 out. Today's bullets effect more lethality per grain

With this said; caliber, caliber caliber! A 500 NE will out perform a 450 NE because of its caliber. However, for a non-PH, the 450NE or 458 Win Mag is all you need with a woodleigh or other bonded bullet provided you can shoot. A PH may want to carry a 500 to stop or turn a charge.

Both of my 450 DRs regulated just under 5000 Ft/lbs, but I'm not concerned because I will use woodleigh bullets.