If you want to do this as a whole experience or for ther dining then ignore me....... BUT! If it is because you are worried you won't see dreams very well, then perhaps you are worrying unnecessarily.
I stood right next to the roped off area a fortnight ago to watch dreams and i turned up at 10:50pm. I never had aproblem turning up a few minutes before and getting a good spot - and I didn't push in or encroach on anyone elses space to do so.