When I was in Jr. High, (1973) I made a lamp. It was a redwood base, that I scorched with a blow torch, and then scraped with a wire brush. The ridges of the grain stood out after this abuse, and it looked an felt very textured. The one Wenge fingerboard I played for a day or two, (fretless) reminded me of this lamp. The grain edges stood out. I don't know if it would have flattened out with more sanding, I returned the bass without altering it. Because the grain made the surface somewhat uneven, I felt that it made the tone somewhat dull and thuddy, lacking in sustain. When I discussed this with a coworker, he told me of his own fretless Warwick with Wenge that he sold for the same reasons. The uneven grain has far more influence on a fretless of course, but that was my experience/impression, FWIW.