I think as with any cichlid you would have to get several (5-6) to get a pair. There is always the chance that all of them will be males or females, in which case...get more

I had a female that started becoming aggressive towards me whenever I walked up to the tank. She was small (5-6") and still showed no fear and was very outgoing.
With chanchos the difference in size between adult males and females is quite big. A full grown male, if it can, will kill the female unless you have a few hiding spots. Ask Reagan, he has probably gone through several chancho females since they keep on getting killed by his big male.
This is the largest growing Amphilophus, so I am assuming you have tank large enough to house these big boys..The one I had grew slowly. You might have sometime to upgrade if you get smaller specimen.
I have seen Reagan's male in person. An adult male chancho is quite impressive.