Cut a disc from a piece of plastic or leather and slip it over the battery post to prevent the terminal clamp from contacting the hold down. There are also plastic hold-down frames that will definitely prevent shorts. The positive cable is the only one that can cause a problem- - - -it doesn't matter if the ground cable comes into contact with the hold-down.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!