I still don't know what "stage five is", but to be (less wordy and)very direct to your question about what is preferable? I would think if you were lean, then everything would move faster; and completion would be reached a lot sooner. But there's always the chance that someone who's very lean is simply really malnourished, and might be quite ill as well, and in this case, thirty days would be a very long time to water fast. One would want to be resting...The thing is, there are no one-size fits all ways to determine sight unseen what occurs on a water fast--that's why the fasts (or it was strongly suggested that anything over three days) were always supervised.
Chiron
PS--I see that Chris has answered this, and states that it would be "preferable" to have more in reserve.