I replaced both of mine.
I used 1/2" aluminum rod to replace the spreaders on my DS II a a number of years ago. The length of the spreader is not controlled by any measurement regulation, but mine were either 22 or 24 inches. I just looked at the old ones in the workshop but the 'bad' ends have been cut off, so I can't be sure of the original length. Let me know if there is any other information you need. It was not a difficult repair.