I started fat cap up and have been doing fat cap down for some time. The biggest reason is that I get a better bark and I still get a moist smoke.
I also started playing around with the drippings from say a brisket. So, I place a pan of veggies in apple juice below and leave them on as long as the smoke.
Here's what I end up with as well as a great butt or brisket:
At this point, I always do fat cap down.