Hi Aldo
I was using an online availability tool called Expertflyer.com. It comes at a cost but give you good inside into availability, seat maps etc. You can try it for free for 5 days, I believe.
For your flights it looks like this:
9 is the maximum number of available seats it will show so as you can see it looks like most classes are wide open on your flights.
C, D, J, Z = Business
Y, B, S = Economy Extra
Rest of them = Economy
I am surprised that you are not able to sign up for upgrade the 21st.
The reason I stated to the other poster that it looked good for en upgrade was because the economy class looked all sold out so they would have to upgrade some anyways.
It does not look like that on your flights.