You might also want to look at the
Wolves from
Thunderbolt Mountain.
They are fantastic wolves, and fit, scale-wise with the Perry's
Hobbit miniatures.
And, I would recommend drilling a hole in the wolf, rather than cutting the tab off the bottom of the rider.
You get a more solid connection that way.
I do wonder about using the newer Wolf Riders, as their riders are cast onto the Wolves, necessitating a lot of work, and possibly leaving a large hole in the back of the wolf that needs to be filled.
But I agree that the Andrewsarchus Mongoleinsis used in the original trilogy for the "Warg Riders" does not really fit with Tolkien's Legendarium.
The Andrewsarchus is indeed a hideous and fearsome beast. But it is a relative of the Horse, and not the Wolf, or Canines and even Canids. Even though it looks like a Hyaena, it is not at all related to the Hyaena.
The choice of the Andrewsarchus Mongoliensis for the Wargs, at the time, was an inspired choice by Jackson, as the Andrewsarchus was native to the lands of New Zealand and Australia when they were still connected to China. But inspired as it was, it was the wrong choice for the Warg based upon Tolkien's descriptions of them.
MB