We were in a Cat 11 -- 6015 which was fairly far forward on the 5/1/04 Magic cruise. That stateroom is turned parallel to the length of the ship but the layout actually gives you more room. We had 3 adults in the room. My mom and aunt had a "normal" category 11, 6101 nearer midship.
The main drawback of the Cat 11s is that they have the single bathroom, instead of the split bath. The main adjustment I made is to put my makeup on and do my hair at the vanity instead of in the bathroom like I usually do. That actually worked out better since the electric outlet in the bathroom is for shavers only and won't work for curling irons. Also, most category 11s don't have the steamer truck so you have less storage space.
The room we had, 6015 will only sleep 3 (no bunk) but 6101 had a bunk. Since the bunk is over the couch you don't loose any floor space.
It was very windy on our cruise and I think I would have enjoyed having a porthole to watch the ocean some of the time when it was windier than I liked up on deck. On the plus side, you can take great naps in the afternoon in an inside cabin!
I think you will have enough room unless you plan to spend LOTS of time in the room. Who knows, you might get an upgrade but as other posters have said, book the stateroom you'll be happy in and if you get an upgrade, that's gravy.