Using parallel and series adapters and harness which I made I have charged 4 each 4S 3300LmAh LiPolys configured as a 8S2P 6600 at 30Amps. or 4.5C. That is a nonimal 960 watts output from the charger.
This was done to prove to my satisfaction that this charger would indeed meet the specification claimed. IMO configuring and using such an array is best left to those with enough knowledge and experience that they do not have to ask how do you do that.
Please do not expect me to give wiring details for these. Once again FMA is developing a safe interface for up to 6S parallel charging.