Either 4 Apaches or 4 Cubo's. I don't know what drivers the Apache favours (I would have to simulate it to say something serious about that), just based on the dimensions I guess it prefers true sub-drivers (plenty of Xmax). The 15-600LF is a good budget driver for Cubo 15 Extended. Perhaps you could contact the designer of the Apache (the name looks familiar).
Best regards
Cubo