Don't let me rain on your parade, Paul. Calibre choice for those don't shoot a lot is simply pick something you want to hunt with.
I'd go with a normal .270 Win before the WSM myself, even though I dislike the .270. Maybe it was O'connor's writing I didn't like which transferred to the round. I think it would probably be excellent for Tahr with a 130gr. TSX or some such bullet - maybe even a standard Nosler Partition.

I even know one guy who's delighted with his 7mm Rem Mag. - I've had a couple myself - not for long though -

I would rather have a .280 Remington for longer distance, smallish big game. The .280, I think, would be great and a better choice by far in my books - better ballanced round for the '06 case as well. I don't have much faith in the 130gr. .270, but do like the 140gr. 7mm - yeah - doesn't make sense, but then, that's how personal choices sometimes drift.

I used to run 2,940fps with 140gr. Noslers in both of my standard 7mm Mausers in a BRNO (24") & Ruger #1(22") - another good round and at least the equal of the .270.

The .280 should add another 100fps to the 7 Mauser - perhaps 150fps.