Heroic Comics 29, March 1945, includes a very strange Vitaman story, Music Master, Flyin' Jenny, and the last Hydroman, most definitely not by Everett! Overstreet says that the painted cover is by Harvey Fuller.
Here's the Vitaman splash page. Done in an odd cartoony style, it's full of fourth wall-breaking and odd gags about superhero conventions. The hero is sort of a budget-basement Hourman, getting his powers (whatever is needed by the plot) by slamming down a handful of vitamin B1 from that bottle around his neck!
Jack