I've used half wounds on fretless for years. Great tone, most of the brightness of a round but the smoothness of a flat. They are a bit sticky to begin with but the more you play them that goes away. They won't harm the fingerboard either. D'Addarios might be best at the moment. I have always used Status halfs but they are not available at the moment and no sign if they will ever return. You could also consider Labella 760FS or D'addario chromes. Flat wound strings but with a tone to die for, much brighter than a traditional stair rod flat and the flexibility of a round.
Just my experience and I'm sure others will chime in with rounds not damaging fingerboards. That's not my experience.