JT,
You don't need to be so defensive of the Korean masters/grandmasters. If you read KJN Hwang Kee's final book, he discusses the Okinawan connection and relationship to our hyung.
Open your eyes and your mind to the early past. That is where all of the answers are...
I was only expressing my belief that studying an art doesn't require studying another art, except for comparison out of interest. Researching a past iteration only shows a historical footnote; you can learn how best to get power out of a form best by doing it.
In regards to Ian's question, most quality books detail the moves for each hyung, but if you want info on a specific part of cho dan, ee dan, or sam dan, I can help you there (more with cho dan and ee dan, since I only learned sam dan a month or two ago). The main thing is to use your hips for power; crossing for blocks and pulling back the retracting hand fast and hard help, but in this form especially waist power is crucial.
In regards to exile's comment about the pyung ahn forms, I agree. I hear they were originally one long form, broken up to make it easier to learn, though I've no details on exactly how that worked. What I do know, though, is that the 5 pyung ahn forms are core to TSD simply because of their effectiveness and variety of moves. At the C.S. Kim schools, black belts now have "required" pyung ahn forms for tests (though we have to know all of them, if we're asked to perform them) just because of how well they teach moves and combinations with stance shifts and all the other little technical things necessary to make the whole form work. Part of the cho dan test, in fact, is performing gi cho hyung sam bu, then all the pyung ahn forms, in sequence, with no choon bee in between forms. Good for in neh, too, I guess.
If they're from Okinawan styles, cool. I'll still practice them Tang Soo Do-style, though.