the category 2's are slightly smaller than the the category 1's. 170sq ft vs 191sq ft. THey are both pretty roomy though. We were in a 2C on the Infinity and our friends were in a 1B. Not a huge difference.
2A, b, c will be on three different decks. A being the highest. If you're prone to sea sickness, go with a lower deck and take the 2C or 1C.
The overhang in the category 1A's is not that bad, we could have used it in Hawaii as our balcony was constantly in direct sunlight and it got pretty hot!
If there is not much of a price difference, go with the larger cabin. Enjoy!
The 1a,b and c's have considerably larger balconies. Category 1b and 1c will save you the overhang problems. 20 or so square feet is not a lot, but in a cabin it can make quite a difference in your comfort level. Check with your t/a for complete details.
If your that flexible I would study the deckplans and look for a cabin that has an oversized balcony. We stayed in 6136 (1C) on Summit and had a balcony that was 3x normal size. Plus being near the suites have some perks as well.