If you still have the ends it might be easier to use those and just make a new one. I had to remake several arms for our 1999 DS. I actually had to make one of the arms adjustable because there was no way to stop the wiper from moving off the glass. It seems at least in past years the WW system is not the chassis manufacturers best ideas and sure not the coach builders either. Most are sorely lacking and often give the owners trouble.
The first thing I did was reduce the length of both wipers about 2-3 inches. One does not need to have the entire WS clear of water and those extra 2-3 inches of a wiper greatly increases the load.
Just some thoughts.
TeJay Auto Instructor/4-yrs USAF/ Liz: RN/ WBGO 2014 Vista 30T/ F-53/CHF/5-Star/Koni * Bella & Izzy * Golden /Cocker mix/ Louie The Cat* All Retired