Shoes, CSMs and 6:5
The tribes must have read some books or hired consultants (or listened to the ShuffleMaster salesman), 'cause right from the start, players had to watch out for CSMs mixed in with the 6 deck shoe tables. And almost every shoe table has an ASM, which is good for fast play and bad for shuffle trackers.
I have yet to see a real SD game, just 6:5. A few places offer DD on a table or two. Unfortunately, I'd say it's 95% or more shoe and/or CSM. I'm really hoping that as they gain experience, they'll add more DD tables.
The real trick to playing in Oklahoma is finding a place and time when a casino is offering "free" ante. As part of the compromise to get around issues on Class II versus Class III gaming, all table games in Oklahoma collect an ante which goes into a prize pool at each casino. IIRC, the ante is $.25 on bets under $3, $.50 for $3 to $50, and $1 for bets $50 and up. Well, $.50 on a $10 bet is a whopping 5% drain on your bankroll. (Common max bet is $500, so $1 ante on $500 is only 0.2%, which is a more manageable drain, if someone can afford the bankroll to bet that high constantly.) So playing during the times when the casino pays the ante for you makes all the difference.