Carol,
Nice looking hives... :)
I've seen people with hives butted up against one another, I try to leave enough room between them to fit my hive tool comfortably so that when I'm trying to work one hive, I'm not jammed up by the one next to it. In a perfect world, more spacing is better, but if you're trying to maximize the use of a stand, I'd say don't worry about it, you "may" get a little bee drift....but that's not really a big deal.