My experience in Okinawan Karate is in Goju Ryu, mainly with Kimo Wall Sensei.
http://www.kimowall.netfirms.com/
I met Wall Sensei at last year's martial arts symposium in South Carolina. A good guy, that's for certain, and I enjoyed the Qi-Gong clinics he conducted for us every morning there.
Hopefully, he'll be back this year.