I usually find them in the just-under-5-pound range. That said, I cook them exactly how I would a boston butt, except the injection and rub is tailored for beef vs. pork. Mind you, a 5lb chuckie is much less thick than a 9lb butt. Where the 9lb butt takes right at 9 to 9.5 hours for me, the chuckie is less than 5, more like 4 to 4.5 hours... I tend to smoke it for about 3 hours then wrap it in foil for the last little while and let it rest for an hour or so to re-hydrate (like a butt). When done properly, the pulled beef has many of the wonderful characteristics that the pulled pork has, but it's BEEF. :-) Leftovers (I'm having trouble the last few years having any of these) make wonderful brunswick stew.
Hance - Lake Dogs Cooking Team - MiM/MBN/GBA CBJ and comp cook
Lake Sinclair, GA (strategically about an hour from everywhere)