I would not pick a specfic stateroom. My husband and I went with the cheapest tickect which was the 1A and we got bumpted up to a 4A. We did have two bunk beds above us but we also had two twin beds that we pushed together. And about the second day we forgot about the two beds above us. It is still early so you would propabley get bumped up.
Booking a 1A GTY is almost a guarantee of a visit from the upgrade fairy. tAs said above, there are VERY few 1A cabins on the Spirit class ships. A true 1A has aonly an upper/lower configuration. To get the 2 lowers you are in a minimum 4A cabin.