The reason I say this has two main reasons:
1: Clay
It's everywhere. The piles of dirt in construction sites are red with the stuff, the banks of creeks and rivers look like blood. The waterways are tinged orange with it. With all this clay you could have almost unlimited ammunition and you would be able to make tons of molds for good stones.

2: Overall, there ain't much there, and its flat.

Oklahoma is mainly plains, and  therefore, there is tons of wide open space to practice in. There aren't many ppl or buildings, just the occasional cows and horses.

But it's only paradise during summer and winter, as more so in summer.
In rthe summer the air is mostly still, so you can practice without wind interference. Incthe winter, it's a bit windier and colder but you can still practice. The climate is awesome in fall/spring, but then again, as show a few weeks/monts ago, the tornadoes can be a bit of a hassle.

That is my piece on Oklahoma.

Nope. Interference, foul on the Tornado.

But if somehow you sling the stone just right into the tornado, and you have a tracker on it, the otrnado coud potentially throw it miles away.