I think you have a couple of issues at work, Steven. First, I think you're right about the meat touching - makes it like one big piece. Also, you'll find the small cuts, for reasons I don't fully understand, take a LOT longer to cook than big cuts. I once did a 4 lb corned beef brisket flat that took 11.5 hours! That's almost 3 hours per pound!
I always recommend sticking with the large cuts for brisket and butts - the more mass (7+ lbs) cook much more evenly and stable.