Sounds like some good smokin' fun, Bob! I think stacked either way would be good, but I wouldn't put a drip pan between them (causes some weird heating issues). Hickory is always a good choice for beef or pork, but I'm not an apple fan for beef. Just probably me, though. Cherry is excellent on both, though. Due to the size difference, on second thought, you might want to put the brisket on the bottom. Let us know how this one goes!