[Bob Faulkner]

I play using Smith compressors on my BSR4EG fretless. The slap sound off a fretless is very different than what you get from a fretted instrument. it sounds a lot less metallic (imagine that!). I slap on my Smith all the time. I wouldn't worry about hurting the fingerboard by playing various styles. Fingerboard wear is an issue to be conscious of over the long haul. I try to avert that by using Smith compressors on my basses. They aren't as smooth as the slicks, but they also sound far more like round wounds than the slicks do.