Gary,
I have a Dean 6 string fretless,and my Alembic Epic 5 string. Each are slightly different, however, the Dean came to me as a new purchase. The factory setup was perfect. Very low action, perfectly straight neck, low string height at the nut. It plays evenly across the complete neck with lots of mwah. Too bad it does not have Alembic electronics. My Alembic was a used purchase that needed setting up and a touch up on the fingerboard from my luthier. Now it's action is slightly higher than the Dean, and the neck has a very minor relief. The playability is superb. Mwah flys off the strings. This baby really sings! I can't put it down. I agree with the comments above, but would state that fretless is a different guitar than a fretted, and because you will play it differently than a fretted bass, the set up will probably be different too. you will need to experiment. I find I use a bit more pressure on the string to get it to sound correctly, so that might take a bit of getting used to.
Kris