Hello,
We had a Cat 7 on the Wonder in May of '02. The opening is about 5 feet wide, and was really more than large enough for a good view. I understand the opening on the Magic is slightly smaller, but I've never been on that ship. On our next cruise we originally booked a 7, but when we had to change the dates, we ended up with a 6. The 7 on the Wonder had a bench seat on one side, and also a temperature and barometer gauge on the wall, which was a nice touch.
Hope that helps,
Take care,
Bill