Having rebuilt a few Tanzbars and as a regular Tanzbar player may
I offer my advice on this subject?  The Tanzbar roll is made of thin
manila card and is shellacked to make it strong enough to hold down
the keys.  These keys directly operate the pallets which sit over the
reed cavities.

One problem is that the key adjustment needs to be heavy enough to
hold the pallets closed against the air pressure on the compression
stroke of the bellows, but not so strong as to damage the roll.  With
experience you know how hard a compression stroke may be on a forte
passage so you adjust the pallets to just not cipher at that time.
A roll in good condition will regularly survive such a duty.

Original Tanzbar rolls suffer from 'back cracking'.  When rolled up
over a long period they lose their flexibility and, on unrolling to
pass through the keyframe, they readily crack across the width of the
roll, with the crack passing between conveniently placed notes, in
the direction opposite to the roll set.  They very quickly become
unplayable.

Another problem with the Tanzbar is that you are playing 'blind'.
You do not know that there is a problem with the roll until it is too
late.  Much too late!  By the time you detect that the roll is running
damaged through the keyframe you will probably have written off the
roll.  My recommendation is always to use rolls is perfect condition,
but before playing your instrument ensure that the keys are correctly
adjusted.

I have recut all my original rolls.  I use manila card, 0.009 inch
thick, which is shellacked after punching and allowed to dry for a week
before rolling onto the spool.  Even after ten years of regular playing
I have not suffered any breakage.  You can also buy new rolls from
Ed Schmidt.

So in conclusion, beware roll repair.  Stick to new rolls and archive
your old ones or send them for copying.

Best regards from GB,
Nicholas Simons