I'm not so sure. We need to be able to borrow money in case of a war - so an air tight balanced budget amendment would not be good. On the other hand if we don't make it air tight then they will work out weasel ways to keep increasing spending for their favorite pork projects.
Assuming I understand correctly, a 2/3 vote in the Senate could modify a balanced budget Constitutional Amendment in the case of needing to borrow during a time of war.