Hey Jason, why don't you try a set of Thomastik Jazz flats. They are very bright sounding, and feel really really nice. You can slap on them if you want to! I really like them. They give you that fretless mmwah sound, but have a lot of definition.
P.S. I really envy you!!! That is going to be a sweet sounding bass! I played a fretless 5 thumb the other day, and it was easily one of the best sounding fretless basses I have ever played. It felt great too. Have fun
