Found @davidhbrown model to be a perfect fit on my bed, I went ahead and remodeled the whole thing in F360 in 1 single part.
Should be almost a 1:1 replica from his FreeCAD model.
The "upper_pins" might be slightly different, but should fit.
Print upside down with Inside out outline setting.
Need a tiny bit of supports on the little inside pins, nothing else.