Typically you would use what is basically the industry standard of 72 cells in series for charging a 24V lead acid battery bank, although I have seen old systems with as little as 60. The reason for the overage is to have enough voltage to float or equalize the batteries in hotter weather when the voltage per cell decreases. Your 24V flooded batteries should need about 29 or so volts into them to get fully charged in a reasonable amount of time, at which voltage, even in cold weather, the panels you describe will see much lowered amps. Two in series with an adequate controller will work, but unless you have an mppt controller it is kind of a waste to have the extra cells above 72 in series as they will contribute essentially nothing to the performance.
