Aligning them is non-trivial because of "wow and flutter" caused by variation of the tape speed. Even if your tape player has perfectly stable tape speed the or

Aligning them is non-trivial because of "wow and flutter" caused by variation of the tape speed. Even if your tape player has perfectly stable tape speed the original recorder wouldn't have had it. Maybe you could calculate some inverse-wow-and-flutter distortion that minimizes the difference between the tracks.