I like leftovers, so I'd figure at least a pound per person & probably more - makes great sammiches later. Simple is good, like Boshizzle, I'd keep it to salt, pepper & garlic - sea salt and fresh cracked black btw.
My favorite primes have been done at around 200, then blasted with high heat at the end for a crust - but that takes a long time and if you haven't done it before it will freak you out because it stays cold for a long time & any logical person will wonder if the roast will ever get done, and then gets up to temp in the last couple hours of cooking. You will have a uniform doneness all the way through with this method. Kinda like a big ole reverse sear. I'd pull it out a around 120 if doing the reverse sear and 125 if just resting it. It'll coast up a little to rare - which is how I like it. Sorry but off the top of my head I can't remember the timing involved - the good new is you can hold prime for awhile and I'm definitely not above adjusting cooking temps to the amount of time I have - it's never seemed to be a problem to ramp up during a cook.
Wood is a personal preference - I like hickory, and oak is great for beef. I'm sure pecan, cherry, etc. are just fine but I can't speak to that from personal experience. The amount is also a matter of personal preference, but too heavy smoke is less desirable than too light.
Another thing you can do is look up the "Standing Tall" prime rib recipe in the Smoke & Spice book - it involves marinating the prime rib in red wine/red wine vinegar overnight & I think there's a little rosemary in there somehere. It's a great recipe.
Absolutely allow it to rest for at least 30 minutes.
Good luck!