Wow, that hurts just thinking about it.
I like to roll the short block around so the deck is parallel to the floor before I lay the head on. If the motor is already in the car I like to drop the top center bolt in and turn it a thread or two in before letting go. Always made me feel like I might be a little paranoid about dropping a head but now I think maybe it isn't such a bad plan. But it isn't just about dropping the head either. I was also trying to minimize the chances of scratching up the teflon surface of the head gaskets.
Glad you guys weren't hurt any worse than you were, I wouldn't be surprised at the loss of a couple toes with that kind cast iron/concrete action. ouch ouch ouch