Our padded arms fit one the same way the back supports do.
Just slide the hooks along the side of the open ottoman.
Arm for 30" is measured at 27" x 19" - 3.5" Thick
Arm for 36" is measured at 30" x 19" - 3.5" Thick
The arms worked just fine.
We love the comfort and convenience of this couch! 4 squares however, do not make a queen sized bed, its short, definitely wide enough but short. You would need 6 cubes to make a real bed. But other than that we truly love the size of the couch, its beautiful, the color is gorgeous and its very comfortable!