The original plastic feet from my AOpen SFF Micro ATX desktop PC case have started to become brittle from sun yellowing and when one snapped, I made a close replacement in F360

I printed them at low quality/detail and the layer lines really show at the top of the protruding foot part. it's up to you if this bothers you enough to print at a higher quality but for me that was fine.

you want to maximize strength in the Z direction so use a straight vertical infil like grid, triangle or tri-hexagon. There are also internal vertical holes so that there are vertical wall shafts that go all the way through for added vertical strength.

Kingroon

Kingroon KP3S

No

No

whatever you want but 3 to 4 walls

15 - 20% with a vertical format

sit the model flat on the bed and it will print without supports. if you do use supports, be careful as cura tends to put them too close to the body and they get stuck

straighforward F360 design: Take measurements, add them as parameters, draw the features on a sketch and extrude as necessary, tweaking and editing the sketch as necessary