I look for a butt in the 7 to 9 pound range, I prefer bone-in, but, it isn't a deal breaker. I do look for nice white fat.
I do all manner of rubs and am not quite sure it makes much of a difference. I use hickory and apple, or just apple. If I find it, peach is also a good option. I am also not so sure wood matters all that much, although in my mind, I prefer fruit woods.
One way to create some more flavor is with a finishing dust. You can make a dust by grinding a normal BBQ rub into a fine powder, this along with some defatted drippings, added back to the pork makes for a fine flavor kick.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"I'm Armenian...perhaps...but then again...maybe not..."