You could find comb anywhere from a couple of feet long to eight feet or more in length (top to bottom) and covering from one wall stud to the other, usually 16" wide. You really need to get all the comb out. You need to tie the brood comb into frames, and hopefully get the queen into the hive body. Then leave the hive close to the area where the nest was, not neccessarily near the entrance they were using. They should find the hive and be in by sundown. Sometimes they don't go in, or all of them don't stay in. I think this is when I didn't get the queen in. Then I beevac them after night fall. Most times they will all end up in the hive body.
Also, the bees will start huddling in corners. Up in the top or down at the bottom. If you open the wall up past the wall studs, or if there is an opening to the other side of the wall stud, the bees will go huddle over on the other side. They don't fly off and huddle many yards away, it will be close to the old nest. So don't tear into the wall past the wall studs, unless you think the colony goes to the other side. You might do like I did on the last one I did and use plastic and duct tape to limit their number of hiding places.