Comparison shot of the two different types.

The small is lower profile, shorter muzzle.
The large isnt really THAT much larger, the nose size is the same but the muzzle is longer and the fit is a little bigger.

I like the bigger one for medium to large sized men and werewolves (as opposed to just anthro-wolves. Its a bit more robust).

I like the smaller one for women, smaller guys, and most sizes of guy who just want a lower profile face.

(The ear size and position is irrelevant, I can do any on either)