In recent weeks, Ace Records has made two new additions to its ongoing Producers Series, and both titles spotlight the versatility of the respective talents, Todd Rundgren and Gus Dudgeon. The Studio Wizardry of Todd Rundgren is, in many senses, an update of Rhino’s 1992 compilation An Elpee’s Worth of Productions.  Like that set, it paints a portrait of the singer-songwriter largely in service of others’ songs, though a handful of his own compositions appear, too.  Ace’s collection spans 1970-1990, when the prolific Rundgren worked his studio magic on essential recordings by…