Not familiar w/Gary Edwin but reading a little seems there is a lot of commonality with my current technique. No shift, compact, right sided. Simple.
Compact: if the human body is 1 unit of space, my swing takes place within 1 unit of space. That is, there is no shift back or fore. In fact, the lower body is in cement, no movement (shift back or up) is possible. Where does the b/s go? Dont know. Dont care. With the core fixed and my "cooked spaghetti" arms, seems to me there is no choice. All I know is I stand in the cement and pick the club up.
Skip a stone over the water: (credit Ben Hogan for the analogy). One could analyze this move and talk of center of gravity, rotation, release of energy into the target, but, Ben even mentions that if you hand a 5 year old a rock and tell him to skip the rock, he'll do it. The mechanics are instinctive.
I just described my golf swing in two steps and thats as simple as it is. How does it relate to Gary Edwin? If you do this you will feel that the swing is totally right sided. The left plays no role in "skipping a stone". As a right handed player, the increase in power (distance) is remarkable. With the classic swing technique, I always fought the negative interference of the right hand. While the hands are supposed to be quiet on the club, my right side dominance would too often prevail. With this technique, there is no struggle between the right and left. The right wins! The left surrendered.
My pro taught me the classic swing. His mantra "hey, your swing is good. Dont worry about hitting the ball, that will come." well, it was too long coming. After much frustration, I broke it down, went into a hitting cage and developed my own technique and for the first time feel my swing is automatic and powerful. And, most importantly, simple. And simple is repeatable.
If the classic swing works for you, fine, but, if you are a struggling golfer give this a try.