I agree! Getting a 1:1 bitwise copy is the utmost importance! Especially of any tapes aged 15-20 years or older. Magnetic tape can be pretty resilient to "bitrot" but, age is the enemy of all metal-oxide storage mediums. I expect a fair percentage of the tape formats to be unusual/outdated/obscure - to the point that even if you find a working drive and dump the data, decoding it is another problem.
