If it's a fretless, I quite loved the Dogal Hellborg round wound ones, but they are beyond expensive, that's what I ended up putting on my Remington Steele.
The Dobbratz brothers put Ernie Ball Slinky on all their basses and on fretted basses, they do marvels, and are a very good option for fretless too.
I wouldn't recommend Elixirs on such luthier instruments as you'd be missing a lot of harmonics and upper mids, which will make your bass sound a bit dull compared to regular strings.
If you like them, the Rotosound RS66 strings, after a few days/weeks, sound quite nice and even.
DR nickels (pick up your favourites) are really great too, but if you prefer stainless steel (again pick up your favourites), they are great too.