Regarding old rolls tearing on re-wind: First, remove the lower brake.
(It is fine when a roll is new with flexible paper.)  Second, pull out
the left roll spool and, if it is loose, wind some tape of your choice
around it.  Then tamp the roll down, so all paper is against the right
spool. Then, before playing the roll, pull out the left spool a bit.

Thus, on rewind the paper can move back and forth and will almost never
tear.  Slow rewinding on fragile paper is important.  As I have said
before, I have used this method for over forty years and have almost
never torn an old roll.

Marc Goodman  
Cleveland, Ohio