I don't think it matters but sos cards will get to 100 of each. I know of only one that has done that and he posted pictures on the TCB guild forum.
"Skinny C.J. Electropretzel" had 800 when he posted.
That was alot of shopping runs .....LOL
I'm not sure how many he has now, but he did solo each of the boss battles in one day.(there was just three at the time 12/18/07
toons are always pushing the limits? 100 cfos in one day, 1,000 unites, and 800 sos cards. But that is the first time i've seen the limit for fires....lol (who would do that many ceos on purpose?)