I think if you take into account the size of the newly opened indoor areas, (even the old one's for that matter), that is more than just the one story/level, and roof area's the area would be substantially larger than the 13 tiles you mention. I think 150 sounds like a good number mabey just slightly high, but if people are mostly playing with some realism, I.e Caution, then the area is plenty big, i would wager about 100 or so would be a nice feel but as rocket has said himself more than once on other issues, it would only be speculation, untill the new map is released.