Hal Kant named after comics editor Hal Kanter.
Originally credited to Jim Mooney, but he has rounder and more relaxed faces than this, as in Tales of the Unexpected #35. The staring, scary eyes can be none other than Vernon Henkel. Also the very thin and broad hat brims are his, only the inking is different. Compare with his signed Chic Carter story in this issue.
Mike Kooiman and Jim Amash state in the Quality Companion that Gustavson created the strip and wrote it. Gustavson's son, Terry Gustafson, concurs.
Letters credit from Terry Gustafson, Paul Gustavson's son.
#711 was killed off just before Brenner was made an editor at Quality Comics.