That's what I thought, "doesn't timber hitch mean with a rope? A rope for lifting rafters? "http://en.wikipedia.org/wiki/Timber_hitch
Going to use a rope rigging? Call OSHA first.
Do like I (the professional rigger ) say, and choke it.
You need straps rated to carry the load. I usually choke and bend over some 16d nails to keep them from sliding. You can use a block of wood too if you think the nails aren't enough. A rope with a timber hitch will work good as a tag line though.
This sounds dangerous if you have to ask these questions. Not harping on you but maybe you should find someone with experience to help you with this. Rigging is usually pretty simple but a minor mistake can lead to a huge accident. A hard hat won't help someone if a beam comes flying on top of them.