I found it helpful to measure the front to back to maintain depth proportion...By standing between storage racks (facing one) & using two dowel rods that rested one on each rack. Move them in so one touches you in front & the other your back at the same level (as if an arrow were shot through you). Mark the spot where they cease to rest on the rack. Then move out & measure the space. Do this at two or three places & use a dowel cut to those lengths & taped inside before stuffing. A friend & I did the duct tape procedure & discovered it flexed too much in the stuffing so lost accuracy.
Apology for lengthy note. We're women. We're wordy. We try to be thorough!
Suchpae