check this
http://www.solarnavigator.net/battery_charging.htm

or

my 2 cent
50 amps output per battery is what i gussed
so i would say 25 amps charge per battery would be kinda safe as a general figure i think it could take more or less when your stopped or WFO
your amperage draw will be determined by voltage any way
if you have crappy current\voltage control i would not use a pwm controller id would use a bunch of contactors
i hope you run WVO that would be nice
if your close to my house bring beer and we will B.S. about your ideas