Flare on Hasselblad Super Wide C.

Hello All,
I have nice old Super Wide of 1959 vintage. This is the camera with the silver lens and shutter release on top. (just after the Supreme Wide Angle)

I have a pretty bad flare problem and have isolated the problem to light striking the cone which surrounds the rear component of the lens. I need some real good flocking material it seems and I need a recommendation.

To date I've tried flat black paint, which cut the problem in half. Then I tried some commercial flocking material recommended for telescopes and cameras and it actually made the problem a bit worse. Part of the solution would be a square lens hood, but I don't know of any for this particular camera.

Anyone have a idea??? Please!

Paul