FIRmaker is able to work with any number of DSP channels. AFMG's general-purpose approach is one DSP channel per cabinet.
In very large arrays it will be possible to combine two or even three cabinets into a single source driven by one FIR DSP channel without too much trade-off.
The number of FIR and amplifier channels used per cabinet is not limited, on the other hand. Dozens of channels could be calculated by FIRmaker per box. Even vertical + horizontal optimization would be possible if implemented by the loudspeaker manufacturer.