3-2-1 is too long for BBs and works better for spare ribs. 2-2-1 is better at 225F. You'll have to find what works best for your smoker, taste, and texture preference. I always wrap BBs with about a half cup of liquid (apple cider usually) because they are leaner than spares and can get dry. You can use any liquid you want from water, beer, OJ, maple syrup, triple sec, chicken broth, bourbon, you get the idea (I've done all those). Start with something easy like apple juice or cider and experiment from there.
On my smoker I do a 2.5-1-.5 at 250F for my tastes for BBs, which is actually my wife's preference, but that took a lot of tasty experimenting.
When you unwrap them, open them carefully and look for about 1/2" draw up on the bone. If it isn't there, seal them back up and go another 15 minutes. Also, save the jus from the wrapping in the refrigerator or freezer after you unwrap them. It makes a great addition to soups, beans, meat loafs, sauces, etc.
Pecan and Cherry mix is a nice choice for pork ribs.