Sorry, I didn't have time to write a tutorial on BaseUI v2. I've added a property to bypass the resize of the DisplayObject (width and height).
It might be useful for a sprite animated that has a size that is changing all time. It will set the useInitialSize to true and you can't use it with a ratio set to RATIO_IN or RATIO_OUT.
The property is:
var el:ElementUI = baseUI.add(mySpriteAnimated);
el.bypassSize = true;