Congratulations on completing a marvelous trek. My wife and I celebrated our 65th birthdays in 2009 by completing the same trek. We enjoyed it so much that we did it again in 2012.
Here is a link to a trip report we wrote.http://hiking.topicwise.com/doc/MontBlanc2012
We are hoping to try the GR5 this September. It is really long so we are aiming for half of the total trek.