The biggest cause of rolls tearing on rewind is the take-up spool
brake, and/or lack of lubrication on the bearings of the take-up
spool.  With the lever set on rewind, (without a roll in place)
test the take-up spool.  It should spin freely.

Disconnect the brake on the take-up spool.  Yes, your rolls will
wind up loosely, but better loose than torn.

Take-up spool brakes were okay for new rolls when the piano and
rolls were new, but we are talking about old and fragile rolls,
70+ years old.

Bruce Clark