BK,
Well it seems that you are ahead of the game, at least in regard to most people, as you know how to do your own setups on fretted bass.
This is a good thing. But, you know how, seasonally, your action changes a little on your fretted bass? And you just kind of put up with it? (or at least, I do, because I'm lazy.)
The thing is, if the action gets a little higher, or a little lower on fretted bass, it still plays and sounds pretty much the same.
However, even a really good fretless bass must be kept in constant adjustment. At least if you want it to really sing all year round, instead of sounding like a thumpy and poor substitute for an upright.
My suggestion to you is to learn to set up your own fretless. And, since you already know how to set up fretted basses, you are way ahead of the game. And it beats the hell out of paying some guy sixty bucks every few weeks.
Kelly