its how you shoot it for sure. Its also bullet choices. I just read a bunch of bullshit by Horace Gore in a magazine..... to many generalities for me to care for his writing.
I prepare for the worst case, and in this case I think the two rounds are very close, but I'd be going 284 personally and see how far I can get energy out of it. Enough energy.
Then I'd do what I had to, to get as close as I could.
Its all pretty damn simple though, take what you want, know its limits, then know YOUR limits in EVERY situation.
Believe it or not I passed shots for over an hour on a bull moose at under 75 yards because I never had a clean shot. Shots to the body at angles and such, yes, but not the clean sure shot I wanted.
But it worked fine, I got the neck/shoulder about 36 hours later with one clean shot.
I'd certainly not question a decent weight TTSX in either round for elk though. Shot within its energy and the shooters abilities on any given shot.