That boat is a Hunter 19 water ballast which I was the top dealer who sold the most with the most experience and knowledge on what to do. Wire or straps underneath that hull will indent the hull with the boat sitting for a long time in that situation. In addition it will affect the tank lid integrity possible busting the seal.
The best advice is to follow the bunkboards as it appears on the trailer for a boat of this type to sit in a lift with the boards facing flat against the hull. . Otherwise the owner will be sorry.