I believe that Monty Roberts does not recommend doing more than 6 (I believe) join ups with the same horse. I would do it a few more times, or until your horse will allow herself to be caught. Any more than is necessary becomes redundant for the horse, and may cause her to become bored and unresponsive. To give you an idea, I worked with a very fearful little arab mare last fall. I had to do the join-up the first time because she wouldn't even let me close to her, nevermind catch her. The first join-up probably took 15 minutes. The next day, she tried to go away from me again, so we did join-up again. This time it only took probably 3 minutes of trotting for her to willingly come to me, and even stand beside me untied while I fiddled with the saddle. If I had continued to work with her, I would probably only have done join-up one more time if I even thought that was necessary.
You do not need to join-up with your horse before you do everything with her. Just establish the principles in her mind, and then live by the concepts. For example, if she moves away from you, put pressure on her to go away until she realizes that the best place to be is with you and comes willingly. It really is a feel thing, so while I can't give you a number, just go by your instincts and what seems to work for your horse.