Thanks, adamclyde. It was delicious.
I have used shoulder before and prefer it. Picnic would work very well too. I had only done CP before in an oven or a kettle (preferred over the oven) but the WSM is the way to go, without question. No heat maintenance issues (like on a kettle) and no roasting pan required. The banana leaves were fragrant and gave up some flavor to the meat but it was not overwhelming--far less fragrant than one finds when steaming tamales. I'm assuming that's because of the dry environment, the lack of steam/water. Smoke penetration was very good--better than I thought it would be. I would make no adjustments to the 'packages' as a result. I had five and put three on top, two on the bottom. Six would have been the most I could do. Doing it solo would be what I'd do but only because of space.
When I get the recipe for the paste/marinade out of my head and typed, I'll post it. You can see waht you think. I use sour orange juice for the paste and a bit more of that, with a little oil, water, and pineapple vinegar to thin it for a marinade.