Your solution is ok, but need clarification.
If your animation is "inside" the div:
<div id="stage_animation_0" class="animation_0"></div>
I suggest to name class attribute with "animation_" + animation number and id attribute with "stage_" + class name.
GET
You can obtain actual timeline position in this way:
var getAnimationPos = function(animation) {
var stage = $.Edge.getComposition(animation).getStage();
var sym = stage.getSymbol("stage_" + animation);
return sym.getPosition();
}
In this way you can obtain your timeline position with:
var position = getAnimationPos("animation_0");
SET
Setting the actual timeline position is more "complicated".
If your animation is playing and you want to jump to a specific position:
var jumpPosition = 300; /* expressed in milliseconds */
$.Edge.getComposition(animation).getStage().play(jumpPosition);
If your animation is paused and you want to set position without play, you have to:
var jumpPosition = 300; /* expressed in milliseconds */
$.Edge.getComposition(animation).getStage().stop(jumpPosition);
In this way, when you'll call play(), animation will start from position 300.