You intend to use these for MI? Realize that the E-130 is not intended for reproduction. Bill Fitzmaurice says it will work well in his DR-15.When people speak of a "K-horn" they almost invariably mean a Klipshorn. Rosie is not a K-horn, it's a Karlson Coupler (Google Karlson and you'll find a web site devoted to it; Freddy Ireson is a contributor there).
From my reading (no direct experience) I suspect the Karlson has a resonance in the 50-70 Hz range that gives the impression of hard-hitting bass response. I'm not sure you'd benefit above 100 Hz.
HTH