Welcome to the DIS!!
I've been on one DCL cruise, and I loved it! We're going again this Feb 14-this time on the Magic!
Your cat 6 cabin has a verandah, right? Very cool! As far as upgrades go, it depends on alot of variables-is the sailing sold out, is there a "need" for cat 6 cabins--these variables mostly depend on the time of year you're sailing. Upgrades are more likely during the off season, when the ship isn't sold out.
There are alot of tips you can get from these boards and from other Web sites. Here are two links that will help
http://www.castawayclub.com/
and
http://www.dcltribute.com/
Also, since you made your reservation yourself, you might consider checking out an online
travel agency and see if you can save some money by transferring your reservation from DCL to a travel agency. There is
Dreams Unlimited, the sponsor of these boards. Alot of DIS'ers use them with great success.
I am using All Seasons Travel-great prices and service!
Here is their link
http://www.allseastravel.com/
There is also a thread called "All the best tips in one place-summarized" Do a search at the bottom of the Cruise Line Forum page and you'll find it!
Anything else, just post and alot of people will be very helpful!!
Again, Welcome to the best forum on earth!!
Ursula