This is the setup I used
.35 mm j-head
.25 mm layer height
125% for first layer
80% rectilinear in-fill
Fan always on except for first layer
2 vertical perimiters
2 bottom layers
2 top layers
This case was designed for .25 mm layer height.
Print a bottom and a top part without support.
Use 4x M3 20mm hex head to fasten.