Well, turns out there was less new material in these books than I though. There was a back-up series, Danny Dreams, about a young boy in the present day who has memories of a past life in caveman times, but those turned out to be reprints as well. So I guess I will just wind this up with the Kubert cover for the final issue, Tor 6 (March/April 76) and move on to the next book.
In 2008 DC would bring back Tor for a six issue miniseries, but the character belongs to Kubert and is not part of the actual DC universe. He even appeared in minseries published by Marvel Comics!