Here in Oklahoma, Spencer Keepers is starting to offer some more classes himself, as well being a great host to many of the big names.
A little known option is Will Andrews at Oklahoma Shooting Skills. I know Spencer has spoken well of him and the foundational type classes seem to be his core business.
I haven't trained with them myself, but TDSA in Tulsa seems to have a decent reputation for a good solid class.
USSA is also has a big facilty in Tulsa.
Mike Seeklander is based out to Tulsa too. Most of his classes seem to be elsewhere though. But if you pay I think he does offer to sync up for a private session.
And as always if you come through OKC area call ahead and if nothing else we'll set you up for a range trip.