True S. Spilopluera, i have no clue. We dont really have any in captivity from my knowledge. They're pretty exclusive to the rivers of Bolivia from my understanding.
The S. Maculatus is what everyone in the hobby knows as Spilo and Mac. They are generally 4-7" in captivity, but I know some keepers have gotten them up to 9-11". They havent been largely imported in years though. They are hard to find, and vendors generally dont have them. You're best bet for finding them is from other keepers, or even trade ins at local fish shops.