Hi! Im planning to buy a Neverfull GM to be used as diaper bag. I found this tote savvy thing to organize Neverfull as Diaper Bag you might wanna consider. In the video she uses a GM size but they said in their blog that MM might also do but a little on the tighter side. Take a look! I'm not personally connected to them but I do definitely want to buy one. https://m.youtube.com/watch?v=-Oiw7MLi_Z4