The grommet size is 3/8 ", I do like the idea of the stick on hooks although I used the over the door method. If you use the stick on method you would probably have to remove another row of pockets as this would lower the hanging unit. You would still have 8 additional pockets for storage though.
I was looking for a simple fix to take advantage of the blank interior of the closet door. A quick search on Amazon turned up this simple hanging bag. For the closet door I simply cut off the bottom row and it fit perfectly. Since there were two in the package I ordered I hung the other on the interior of the bathroom door. I do not use the shower in the bathroom but if you do you could simply remove the storage bag so it doesn't get wet. The hanging hooks took a little bending with some pliers to get a good fit. The price was certainly right and the quality seems good. Hope someone else will find this useful. https://www.amazon.com/gp/product/B06XSQTB59/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1