Two questions, really:
Are the King beds on Splendor and Grandeur true US king-sized beds?
How do they split them if two beds are desired? Will they put the nightstands between the two beds?
It partly depends on which suite you are considering. The G cabin beds are smaller. The Regent Suit is bigger.
That said, for standard F thru A cabins, the bed size is “about” 68 inches wide and 74 long, when set up as a King. I am measuring a bed on Explorer. The bed frame is actually 2 frames pushed together. The top of the mattress has a zipper to connect both halves together.
For 2 twins, the halves are separated. The bed stands will be placed in between.