Sometimes you just can't get around having to add weight if you don't want to move anything else but if you do add the stick on weights just make sure they do not fall off . If I have to add weight I try to make it a working weight such as an on board glow system which requires a battery to get the plug going, sometimes a larger engine if possible, anything you can think of other than dead lead. In your case I don't think moving the battery up front is going to help much if 6 ozs. is what you had to add to get it to balance.
Try to do what ever you can to not have to add lead but if that is the only thing to do then just make sure it does not fall off and go fly.