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 darn near anywhere)
Started competing in chili cookoffs back in the 1990's and have competed in more than I care to count. I became a CBJ in MiM in 2005, then MBN and in GBA in 2010. I've probably judged 130+- BBQ comps (sanctioned and unsanctioned) over this time. That said, I really enjoy competing more than I enjoy judging, and hope to get back to doing 4 or 5 a year in the near future.