Congratulations! That ride is tough enough on a single bike, on a tandem it must be really hard. We did some of the route last year on our tandem (we went up & down south side of Galibier and did Alpe d'Huez) and really enjoyed it. We've done a couple of sportifs with the tandem, and in the mountainous ones we are often the only tandem, which is a shame (but somewhat understandable).
There are a huge number of participants in the Marmotte, how did it go handling the tandem in the big crowds near the beginning of the race?