Who said that you should only use Leica lenses on a Leica?
Super-Wide Heliar 4.5/15, Ultron 2/28 and Color Heliar 2.5/75
Those “CV” (=Cosina Voigtländer, because they are made by Cosina) are great performers and give the photographer a nice feeling of a solid built.
That’s definitely good enough for me. 😉