that's a good question.
each tween uses about 208 bytes of memory compared to a barebones movieclip that uses 752 bytes of memory. so, if you had 100 tweens that would use ~ 208 * 100 / 1024 ~ 20.3kb.
and there's no easy way to detect when (of if) any particular object has been removed from memory. you can use adobe scout to profile your project to see how it handles (among other things) memory as it plays, and you can use some of the System properties (like totalMemory) but that's about as much as you can do.
btw, your myTween is NOT the same as Tween1. it's just a variable pointing to Tween1. so, you're NOT making Tween1 eligible for gc with your code. you would use something like:
var Tween1:Tween = new Tween(myMovieClip, "x", Back.easeOut, 474.5, 407.5, 2, true);
function doneMovingMC (e:TweenEvent):void
...so, you're NOT making Tween1 eligible for gc with your code
. By "gc" you mean 'garbage collection'?
Thanks for the clarification regarding 'myTween' just being a pointer. I wondered about that.
yes, gc = garbage collection.
(and you're welcome.)