As far as 1st come 1st served is concerned, to me it seems like the most natural approach, but it might exacerbate the backing out problem. When the last person in line sees that they are getting the road view on the lowest floor, they might back out, and it could jeoprdize the entire deal.

Maybe we go for half of what we think we can buy. We will make sure we have twice as many "troops" as we think we need. That way, when some inevitebly back out, we still have plenty of others who we know have made their cash available and are interested in that particular deal, who can take their place.

Some will obviously be left behind but there will always be more deals comming down the pipe.