Keeping the wire straight is not all that important. You would think it would be critical but you will be able to work stations with one end of a dipole laying on the ground, not suggesting it but like most have done it.
Personally I would keep the wire out of reach of anyone touching it. There are a lot of alternatives. Hang it from your balcony door frame and run each side of a dipole out each side of your balcony. Should be able to get 32' feet and the ends be off the ground. Learn to make your own antennas You will be surprised at how easy it is to build an effective radiating element.
Raduino bracket and Ham_Made_Keys