Also important to mention here that when creating the era1 files (and thus the torrent), the exact result might differ cross client and cross client versions. This is due to the fact that Snappy compression is used which will have non-deterministic output over different implementations/versions.
It is not an issue for the verification part however, as that is based on SSZ hash_tree_root and has already been explained/addressed in above discussion.
I agree that having eip7643-proofs.txt in the torrent can come in handy for verifying only certain eras of the torrent.