Thank you so much! Fun description, because I also wanted this for Celeste. :)
The buttons fit the DS4 perfectly. I printed with .2mm for initial layer then .08mm layer height and used ironing on the top. I will probably still end up sanding them a little, but this improves the feel of the d-pad so much.
In case it's useful information for anyone, the DS4 doesn't appear to register opposite directions simultaneously. It will release both directions until one button is released. For me, the perk of this is to feel button presses more, especially when going from 90 degree to diagonal.