A 20# pig? Keep it and feed it till it's 80-100#'s. You might get a couple sanchos out of a 20#. I've never done a 20# pig, seen thousands of them and the last thing I thought about was stick'n one on a smoker.
Feed that little thing till it has some meat on her bones.
I've never done one, but if I did.....I would'nt smoke/bbq anything less than a 50 lber. If you're gonna do the trouble, at least have something to show for it. But hey, I truely hope it turns out drippin tasty!
I cook 200lb because they are the right age and size for good meat. Never heard of doing one so small......I kinda agree with the others Feed it some more and wait a couple of months for pig....I like mine skinned and cooking at 350 seems way to high. If you do it I would be intrested in the outcome.