Dropped from 7.5 to 6 last week and it smoothed out but still had side stuff, so I went down to 5 a few days ago. Way gentler now. Lost a kg last round so sticking with 5 for now.
You've probably fought plenty of battles over the years. Anyway, some tattoos use super fine needles at 1mm depth. I do that depth regularly in my own practice. Could show you sources but I know you won't change your mind anyway.