TDF TIckets in early August?

So, a friend of mine and myself are planning to visit NYC this summer, in early August, and we are planning on joining TDF so that we can get discounted tickets. We are both students. I was wondering what the chances are of being able to get the following shows off of TDF before we go?

Promises, Promises
Enron
Next Fall
A LIttle Night Music
American Idiot
Mary Poppins
The Addam's Family
La Cage Aux Folles
Next to Normal.

These are all shows that we are planning on seeing, so I was just wondering if we should wait to buy them from TKTS on the day of, (if we can't buy them from TDF) or we should just buy them in advance. I like to have everything planned and organized, so I generally lean towards paying full price for a ticket, just to have that comfort of knowing.

The only problem is the waiting game....how long do you feel comfortable waiting to SEE if it comes up on TDF. The b'way shows often are only posted a week in advance.

BUT to be honest, I am not as confident as Jordan is on the availability on TDF for most of those shows.

I'm still waiting for Bloody Bloody to show up for next Week!

---