I was using square towers with one sandbag wide openings. In my first raid, however, the attackers approached from the corner direction and I couldn't shoot at them at all because the angle wasn't right. So then I switched to two sandbag wide openings which offered greater arcs of fire.
I've gone through half a dozen different tower designs now and am still experimenting.
I've gone through half a dozen different tower designs now and am still experimenting.