At the end of my shoulder rehab mode I'm looking to do the Big 21 also. I was trying to remember what Dan had said about starting weights and this was Dan's comment from his t-nation article:
"We go to "heavy"...sorta max, the week before in all three lifts. Don't...by God...base it on Max Max Max...you will be dead.
At the end of nine workouts, you try to add five...maybe ten...pounds to that sorta max in testing. Don't do what some of my athletes do: Coach, I got 185 in the snatch and in nine workouts I think I will get 225."
"And for crying out loud. Don't go into the pain cave. I can't stress this enough. Your Totem Animal won't be in there to help you. You'll be on your own. The Pain Cave is for cowards.
Pain is your companion, don't go hide from it."