the sanyo bipolar process CR23 is especilly amied for large current circuit. but spice model (Gummel-Poon model) only provide npn model with emitter area(10.5um*10.5um).
i used it to design a class ab audio amplifier with peak output current about 3A.
how can i use it to design power stage ? parallel many many that npn or merged with large emitter area??
Ask a process guy who is responsible for the models and/or (layout) devices. I think your large emitter area will be considered unknown modeling territory.
And try to get ALL your current densities (metal, transistors, vias and contacts) down to acceptable levels.