Chuck Roast or Chuck Roll

I've been hearing good things about Chucky's or chuck roasts on the forum, so I've been on the hunt for one.
My local butcher has 2-3 lb roasts for for $5.99 lb, or he'll sell the entire 17-18 lb chuck roll for $4.99 lb. I don't need the entire chuck roll, but the smaller roasts just aren't enough. They will also cut whatever size I need/want, so here are my questions.
There will be 12 people here, although this being suburbia, more might come over due to the aroma, so I'm thinking a 6-8 lb roast will ensure leftovers. AGREE?
SHOULD I BUY THE RIB SIDE (MORE FAT) OR THE NECK SIDE (LESS FAT MORE MEAT)?
Does beef have a stall like pork does?
I'm cooking on a UDS with temps (at the grill) about 225 to 235. I am going to budget 1.5 hours per lb w/ a 2-4 hour foiled in cooler time as well and a 12 pack of Amstel Light. AGREE?
PULL @ 140 TO 145, AGREE?
If anyone has any more tips, I'd love to hear 'em.
Thanks in advance for all of your sage wisdom.

Thanks for the answers thus far. This butcher has always been expensive, but the meat is extraordinary. It's alway graded at choice, but choice, in it's own right, has a very large disparity with a huge difference between the low and the high of the USDA ranking.
Sooo, should I get the neck side ot the rib side?
I'm going to pull the beef.