Print two of the protectors. I succeeded with 100% infill to make them really strong.Find 20 inch of adhesive magnetic strip (7mm high) cut it in four pieces and glue it into the rails I left for them.I added the FreeCad file in case you want change any dimensions according to the size of you bench vise.
Some experience (+2000 printing hours) with UM2, designing with onCad, FreeCad, OpenSCad and Blender.
Newly acquired an Ultimaker S3 which prints super reliably