Wow, Mt Blanc.
There is a good article if albiet a bit short about climbing/trekking Mt. Blanc in Time Magazine this month.
From my limited knowledge of Alpine stuff I'd say be preparred for a 2am start for the summit from your hut and a couple of very long days out. Also check if/when the huts are open and you might need to book.
Weather is a problem though, getting it just right is a pain, I've just come back from Slovenia after booking a trek up Mt. Triglav until the weather got in the way, ARSE!
Good luck all the same!
Take some good pics!