Felt dismissing the story was too harsh (OK, there were some problems like Superman hearing Black Zero's two hearts only once, but many stories have relatively minor errors).
As far as the connection with Tomar-Re is concerned, the following link gives the story:
https://www.supermanthroughtheages.com/tales2/greatestGL/In this story "The Greatest Green Lantern of All", Tomar-Re's mission to save Krypton is thwarted by an accident, and he only manages to reach Krypton in time to see it explode.
I can't see that this is a problem with Black Zero's relevation? Tomar-Re and Black Zero don't meet.
The Wikipedia link qoutes Bridwell's suggestion that what Black Zero had noticed was Tomar-Re's attempts to prevent the destruction, and that the two sets of interference somehow cancel each other out, seems rather contrived in order to try and preserve the accepted story-line of Jor-El prediction of the destruction of Krypton?
[Admittedly, I couldnt find any link developing Bridwell's argument.]
Another site that people might find useful is:
http://www.mikesamazingworld.com/database/index.phpSome stories are placed on the site in their entirety.
Cheers, Jimmy-Neutron