For what it's worth I've use Equithotics, the sneakers for horses for
years. I also tried the Flex Step shoes, what a mistake! The
Equithotics, on the other hand, I love. They aren't particularly good
for riding in snow or ice, they slip. But, you can get inserts for
screw in studs from the Equithotics people, just call and ask for some.
The main drawback I had when I left the front shoes on my horses last
year and used these inserts was that the inserts are only designed to go
in the heel. You can put one in the toe, but you have to drill out on
of the tungstun studs in the toe. We opted not to do that. Then, I put
the Easyboots with the studs in them on the back feet. The 3 studs in
the Easyboots provided much better traction than the 2 in the heels of
the Equithotics. And, I liked the fact that my horse was standing level
on her feet when I had to cross over a road or other hard surface. All
you have to do if you don't want the studs is unscrew them and stick a
plug into the insert to protect the threads. The plugs can be bought at
any farrier supply house.
Hope this provides the information you were looking for.
Lyn