That should work, unless you have some other event or action that's setting the width to something else... in your loop though, every object would be resized to the same size - since it would be picking every instance of that object and resizing it (so maybe it is working but they're all the same size and probably overlapping?)
You will need to add a way to only allow the resizing to work once per object - so you can have a boolean instance variable that changes to on or off (whatever your preference) and add that condition as a sub event to your loop and move the resize action to that sub event - and make sure you trigger the boolean change after you resize so it doesn't resize each time the loop is run.
Hopefully that makes sense.
~Sol