The VW wipers always have bugged me a bit - even after I painted them silver. I decided to order a pair of correct arms and blades from Sierra Madre and see what I could come up with - that hopefully did not include changing the linkage.
To my surprise, the repo arms fit on the VW posts. They sat a little tall, so I drilled the internal mount on the arm (for depth, not width) which allowed the arm to drop another 1/8 - 1/4 of an inch. While it did appear that tightening the bolt on the arm would hold them on just fine, I had a very bad experience with mis aligned wipers hitting new paint many years ago, so I made one last/quick modification. I made some alignment reference marks on the glass (with a sharpie), pulled the arms off and took a file to the post, creating a flat area, just to make sure that the bolt had maximum contact with the post. They work fine and look the part. Pretty pleased.
These things really are just the biggest model cars ever. Very fun to tinker on.