My PH was very happy I was using a 375H&H with 300 grain SAF's.
The shot on the right shoulder turned it to mush.
Took another shot to anchor him and then a finishing shot.
I know others on AH have taken Eland with 7mm's and .30 calibers.
Personally, I don't see anything wrong with a 35W and 225 grain NAB's.
However there are many who are way more experienced than I am about these animals.
Just be ready with a follow up shot, from what I hear they can be hard to bring down.