>>72669 (OP)
>Another question I have is should I try and go for Pampers Size 7 or Underjams and then wear the Goodnites over those to create a feeling of an adult diaper?
21 y/o M here. Let me say, don´t try to fit into a pampers 7. I still haven´t had a chance to try them, but I was fortunate enough to try the 6+ which are pretty small. I´m really skinny for my age, so they barely fit, but they are really small and the size 7 are just 2 cm wider. You´d be better off buying actual Tena diapers or some actual ABDL diapers.
And wearing on top of each other will just make it bigger. This doesn´t feel anything like an adult diaper, at all.