Definitely check out the videos available in the honeybee removal section. JP, Hardwood, and others post a bunch of them. Watch a bunch of them. You will learn a lot. Watch how the beeks move, what they are doing with their hands, rubber bands on the frames, how they cut into walls, etc. It sounds like you have a co-operative owner, so you will probably be able to leave a hive set up there for a day or two to collect stragglers. Good luck!