Depends on what your prefernces are. The caudopunks don't use shells all that often, and sometimes tend to school and roam. They get up to @ 4 inches or 10.5 cm. Ornatipinnis are more homebodies and tend to stay more in a claimed territory, and are smaller, but have a bit less coloration.
With the tank you're setting up, IMO, probably ornatipinnis will be a better fit.

 

I would get either L. brevis (pair), or L. multifasciatus (trio), because either of the species you want need bigger tanks.