Didn't know they were expensive. They don't have to be large. But medium size like rose line or filament are good choices. Not sure about price where you live.
Pink tail Chalceus are different that red tail barracudas. That's still a good alternative for a top zone fish. I have 6 Chalceus and are very good hardy fish.
Not to derail your thread man but i was curious.... being in south africa are i would think tons of cool polys would be available to you. Is that true or are they sold overseas asap