Smoked beef ribs cook time

I picked up a nice 1/2 rack of beef ribs this morning. I've never cooked them before, and I can only remember eating them once before. I rubbed them with some olive oil and sprinkled on some montreal steak seasoning, and they went on the egg at 250 degrees at 1pm. I figured I'd start basting them with butter after a few hours, and doubt I'll use a sauce on them. I checked one of my bbq cook books and it said 6-8 hours at 250 degrees, which was longer than I expected. Any advice on cooking time or how to know when they are done would be appreciated.

I'm about to pull some salmon off and put some pork ribs on, so if the beef ribs don't turn out good, I won't be going hungry.