If you get ice cover for more than a week at a time, stocking CNBG is most likely a waste. My bet, even if they do survive they're going to do poorly. If you want variety, why not trying a different species of sunfish? PS, LES, RBS, RES, etc...
If I could find a supplier for PS, LES, RBS I would look into getting some of them, but not sure anyone is close to NE Oklahoma.
Now as far as the CSBG go I would like to have some of them as well, but since not too many people that close to me want some Rex does not get close enough to me to have them delivered, so I would have to catch up with him and it may be 200 miles away from my ponds. But will keep it in mind just in case he has some other fish I want as well and I can get them all at one time.