The 17 stuff is the best but IMHO, you'll make a fox messy at least some of the time no matter what you do minus shooting with a rimfire which I cannot recommend for all-purpose use.
I'd use a Vmax of some sort in 17 or 20 caliber and make it leave the muzzle at about 3K...
Wisconsin reds are more likely larger than our 8 pound Texas grays...
